#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#define see(x) cout  <<"<DBG> " << #x << ": " << (x) << endl
#endif
#ifndef LOCAL
#define see(x)
#endif
template<typename T> void dprintln(const T &t) { cout << t << endl; } // for debug use
template<typename T, typename ...Args> void dprintln(const T &t, const Args &...rest) { cout << t << ' '; dprintln(rest...); }
template<typename T> void println(const T &t) { cout << t << '\n'; }
template<typename T, typename ...Args> void println(const T &t, const Args &...rest) { cout << t << ' '; println(rest...); }

template<typename T> void print(const T &t) { cout << t << ' '; }

template<typename T, typename ...Args> void print(const T &t, const Args &...rest) { cout << t; print(rest...); }

// this overload is chosen when there's only one argument
template<class T> void scan(T &t) { cin >> t; }
template<class T, class ...Args> void scan(T &a, Args &...rest) { cin >> a; scan(rest...); }
using ll = long long;
using vl = vector<ll>;
using vi = vector<int>;
using pii = pair<int,int>;
using vb = vector<bool>;
using vpii = vector<pii>;

#define rng(i, a, b) for(int i = (a); i < (b); ++i)
#define dwn(i, b, a) for (int i = (b); i >= (a); i--)
#define rep(n) for(int _ = 0, __ = (int)n; _ < __; _++)
#define stp(i, a, b, c) for (int i = (a); i < (b); i += (c))
#define FOR(x, cont) for (auto &x: cont)
#define all(x) (x).begin(), (x).end()
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define SZ(x) (int)(x).size()
#define pq(T,COMP) priority_queue<T, vector<T>, COMP>
#define popcnt(x) __builtin_popcount((x))
#define SET(arr, v) memset(arr, (v), sizeof (arr))
#define UNIQ(vec) (vec).erase(unique(all(vec)), (vec).end())
auto bet = [](const ll x, const ll y, const ll i) {
    return x <= i && i <= y;
};
inline int h_bit(unsigned int x) {
    return 31 - __builtin_clz(x);
}
inline int h_bitll(unsigned long long x) {
    return 63 - __builtin_clzll(x);
}

struct frac{
    using ll = long long;
    ll fz, fm;
    frac() = default;

    frac(ll fz, ll fm) { // 构造函数变量名最好不要跟类成员名一样！
        assert(fm != 0);
        if (fm < 0) fm *= -1, fz *= -1;
        ll g = __gcd(abs(fz), fm);
        fz /= g, fm /= g;
        this->fz = fz, this->fm = fm;
    }

    frac(ll x):fz(x),fm(1){} // implicit conversion

    frac operator*(const frac &other)const{
        return {fz * other.fz, fm * other.fm};
    }

    frac operator-()const{
        return {-fz, fm};
    }
    frac operator-(const frac &other)const{
        return *this + (-other);
    }
    frac operator+(const frac &other)const{
        ll _fz = fz * other.fm + fm * other.fz;
        ll _fm = fm * other.fm;
        return {_fz, _fm};
    }
    bool operator==(const frac &other)const{
        return other.fz == fz && other.fm == fm;
    }
    bool operator<(const frac &other)const{
        return fz * other.fm < other.fz * fm;
    }
    bool operator>(const frac &other)const{
        return fz * other.fm > other.fz * fm;
    }
    bool operator>=(const frac &other)const{
        return !(*this < other);
    }
    bool operator<=(const frac &other)const{
        return !(*this > other);
    }
    frac operator/(const int &x)const{
        return {fz, fm * x};
    }
    double to_double() const {
        return fz / (double)fm;
    }

};

template <typename T>
struct bit {
    vector<T> a;
    explicit bit(int n, int v = 0) {
        a.resize(n + 1);
        if(v != 0) {
            for (int i = 1; i <= n; ++i) a[i] = v;
        }
    }

    T sum(T x) {
        T res = 0;
        while (x) {
            res += a[x];
            x -= x & -x;
        }
        return res;
    }

    T sum(int l, int r) {
        if (l > r) return 0;
        return sum(r) - sum(l - 1);
    }

    void add(int x, T v) {
        while (x < a.size()) {
            a[x] += v;
            x += x & -x;
        }
    }
    void clear(){
        fill(a.begin(), a.end(), 0);
    }
};
vi get_prime(int n) {
    vi minp(n + 1), p;
    for (int i = 2; i <= n; i++) {
        if (!minp[i]) {
            minp[i] = i;
            p.pb(i);
        }
        FOR(x, p) {
            if (x <= minp[i] && x * i <= n)
                minp[x * i] = x;
            else break;
        }
    }
    return p;
}

const int mod = 1000000009;

inline void add_mod(ll &x, const ll &y) {
    x += y;
    if (x >= mod) x -= mod;
}
void sub_mod(ll &x, const ll &y) {
    x -= y;
    if (x < 0) x += mod;
}
// alias templates
template<typename T> using vv = vector<vector<T>>;
template <typename T1, typename T2 = T1> using vp = vector<pair<T1,T2>>;



using vec = vector<ll>;
using mat = vector<vec>;
mat get_I(int n) {
    mat res(n, vec(n));
    for (int i = 0; i < n; i++)
        res[i][i] = 1;
    return res;
}

mat operator*(const mat &a, const mat &b) {
    mat c(a.size(), vec(b[0].size()));
    for (size_t i = 0; i < a.size(); i++) {
        for (size_t j = 0; j < a[0].size(); j++) {
            if (a[i][j]) { // optimization for sparse matrix
                for (size_t k = 0; k < b[0].size(); k++) {
                    add_mod(c[i][k], a[i][j] * b[j][k] % mod);
                }
            }
        }
    }
    return c;
}

vec operator*(const mat &a, const vec &b) {
    vec c(a.size());
    for (size_t i = 0; i < a.size(); i++) {
        for (size_t j = 0; j < a[0].size(); j++) {
            add_mod(c[i], a[i][j] * b[j] % mod);
        }
    }
    return c;
}

mat pow(mat a, ll n) {
    mat res(a.size(), vec(a[0].size()));
    for (size_t i = 0; i < a.size(); i++) {
        res[i][i] = 1;
    }
    while (n) {
        if (n & 1) {
            res = res * a;
        }
        a = a * a;
        n >>= 1;
    }
    return res;
}



vi get_popcnt(int n) {
    vi res(n + 1);
    rng (i, 0, n) {
        if (i * 2 <= n) res[i * 2] = res[i];
        if ((i & 1) == 0) res[i + 1] = res[i] + 1;
    }
    return res;
}

/**** SUPER MACROs ****/
#define FAIL {println("NO"); return 0;}
const int N = 100005;
int fa[N];
int find(int x){
    return fa[x]==x?x:fa[x]=find(fa[x]);
}

//void unite(int x, int y) {
////    x = find(x), y = find(y);
////    fa[x] = y;
////}
struct edge{
    int u, v, w;
    void read(){scan(u, v, w);}
    void read2(){scan(u, v);}
};

vector<pii> g[N];
int dis[N];
int par[N][18];
int max_w[N][18];

int dep[N];

bool vis[N];
void dfs(int u) {
    vis[u] = true;
    FOR(e, g[u]) {
        int v = e.first, w= e.second;
        if (!vis[v]) {
            dep[v] = dep[u] + 1;
            max_w[v][0] = w;
            par[v][0] = u;
            rng (i, 1, 17) {
                int t = par[v][i-1];
                par[v][i] = par[t][i-1];
                max_w[v][i] = max(max_w[v][i-1], max_w[t][i-1]);
            }
            dfs(v);
        }
    }
}

int LCA(int u, int v) {
    if (dep[u] < dep[v]) swap(u, v);
    int dif = dep[u] - dep[v];
    int mx = INT_MIN;
    rng (i, 0, 17) {
        if (dif & 1 << i) {
            mx = max(mx, max_w[u][i]);
            u = par[u][i];
        }
    }
    if (u != v) {
        dwn(i, 16, 0) {
            if (par[u][i] != par[v][i]) {
                mx = max(mx, max(max_w[u][i], max_w[v][i]));
                u = par[u][i];
                v = par[v][i];
            }
        }
    }
    return mx;
}

// f[n][k] = f[n-1][k] + f[n][k-1]*n
int main() {
#ifdef LOCAL
    freopen("main.in", "r", stdin);
//    freopen("main.out", "w", stdout);
#endif
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, m1, m2;

    cin >> n >> m2 >> m1;

    vector<edge> e1(m1), e2(m2);
    FOR(e, e2) {e.read2();}
    FOR(e, e1) e.read();

    sort(all(e1), [](edge a, edge b){return a.w < b.w;});

    rng (i, 1, n+1) fa[i]=i;

    FOR(e, e1) {
        int ru = find(e.u);
        int rv = find(e.v);
        if (ru != rv) {
            g[e.v].eb(e.u, e.w);
            g[e.u].eb(e.v, e.w);
            fa[ru] = fa[rv];
        }
    }

    rng (i, 1, n + 1) {
        if(!vis[i]) dfs(i);
    }

    ll ans = 0;
    FOR(e, e2) {
        println(find(e.u), find(e.v));
        if (find(e.u) != find(e.v)) {
            println(-1);
            return 0;
        }
        ans += LCA(e.u, e.v);
    }

    println(ans);



#ifdef LOCAL
    cout << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " s.\n";
#endif
    return 0;
}