#include <bits/stdc++.h>
#define int int64_t
#define ii pair<int, int>
#define fi first
#define se second
using namespace std;

const int MAX = 1e3+6;
const int MX = 1e15;

int n, d[4][MAX], m1, m2, st, en, f[5][MAX], vs[5][MAX], dp[MAX][MAX];
std::vector<ii> g[3][MAX];
int res;

void Dijkstra(int num){
    for(int i=1; i<=n; i++) d[num][i] = MX;
    priority_queue<ii, vector<ii>, greater<ii> > pq;
    d[num][en] = 0;
    pq.push(ii(0, en));
    while (!pq.empty()){
        int u = pq.top().se, du = pq.top().fi; pq.pop();
        if (du != d[num][u]) continue;
        for(int i=0; i< g[num][u].size() ; i++){
            int v = g[num][u][i].se, uv = g[num][u][i].fi;
            if (du + uv < d[num][v]){
                d[num][v] = du + uv;
                pq.push(ii(d[num][v], v));
            }
        }
    }
}

void BFS(){
    queue<ii> q;
    q.push(ii(st, 1));
    while (!q.empty()){
        int u = q.front().fi, type = q.front().se; q.pop();
        // cout << u << "\n";
        for(int i=0; i<(int) g[type][u].size(); i++){
            int v = g[type][u][i].se, uv = g[type][u][i].fi;
            if (d[type][v] < d[type][u]){
                // cout << u << " " << v << "\n";
                if (vs[u][v]){
                    res = -1;
                    return;
                }
                if (f[type][u] + uv > f[3-type][v]){
                    f[3-type][v] = f[type][u] + uv;
                    vs[u][v] = true;
                    q.push(ii(v, 3-type));
                }
            }
        }
    }
}

void DFS(int u, int type){
    vs[type][u] = 1;
    for(int i=0; i<(int)g[type][u].size(); i++){
        int v = g[type][u][i].se;
        if (d[type][v] >= d[type][u]) continue;
        if (vs[3-type][v]==2) continue;
        if (vs[3-type][v]==1) {
            res = -1;
            return;
            continue;
        }
        // if (u==1 && v==4) cout << "SF\n";
        DFS(v, 3-type);
    }
    vs[type][u] = 2;
}

int DP(int u, int type){
    if (u == en) return 0;
    if (dp[u][type] != -1) return dp[u][type];
    dp[u][type] = -99999999999;
    // cout << u << " ";
    for(int i=0; i< g[type][u].size(); i++){
        int v = g[type][u][i].se, uv = g[type][u][i].fi;
        if (d[type][v] < d[type][u]){
            dp[u][type] = max(dp[u][type], DP(v, 3-type) + uv);
        }
    }
    return dp[u][type];
}

signed main(int argc, char const *argv[])
{
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    // #ifndef ONLINE_JUDGE
    //     freopen("input.txt","r",stdin);
    // #endif

    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    #ifndef ONLINE_JUDGE
        freopen("TOUR.INP","r",stdin);
        freopen("TOUR.OUT","w",stdout);
    #endif

    cin >> n >> st >> en;
    cin >> m1;
    for(int i=1; i<=m1; i++){
        int u, v, w;
        cin >> u >> v >> w;
        g[1][u].push_back(ii(w, v));
        g[1][v].push_back(ii(w, u));
    }
    cin >> m2;
    for(int i=1; i<=m2; i++){
        int u, v, w;
        cin >> u >> v >> w;
        g[2][u].push_back(ii(w, v));
        g[2][v].push_back(ii(w, u));
    }

    Dijkstra(1);
    Dijkstra(2); // en

    // cout << -1;
    // return 0;
    // BFS();
    memset(dp, -1, sizeof dp);
    DFS(st, 1);
    // cout << "XO";
    if (res==-1) {
        cout << res;
        return 0;
    }
    // DP(en, 1);
    // DP(en, 2);
    cout << DP(st, 1);
    // cout << max(f[1][en], f[2][en]);
    return 0;
}