#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
#define fi first
#define se second
#define sz(a) ((int)a.size())
#define pb push_back
#define int ll
const int inf_int = 1e9;
const ll inf_ll = 1e18;
const int MAXN = 2e5+100;
const int MOD = 1e9+7;

bool debug = 0;
#define dout if(debug) cout
vector<int> g[MAXN];
vector<int> to_big[MAXN];
ll val[MAXN];
int s[MAXN];
int used[MAXN];
int check[MAXN];

int block = 500;

int cnt[MAXN]; // for all
int inc[MAXN]; // for big

inline void add(ll &p1,ll &q1,ll p2,ll q2){
    p1 = (p1*q2 + p2 * q1)%MOD;
    q1 = (q1 * q2)%MOD;
}

ll pow_2[MAXN];
ll rev_pow2[MAXN];
int add_last[MAXN][210];

ll binpow(ll a, int n) {
	ll res = 1;
	while (n) {
		if (n & 1){
            res = (res * a)%MOD;
		}
		a = (a*a)%MOD;
		n >>= 1;
	}
	return res;
}

inline ll rev(ll x){
    return binpow(x,MOD-2);
}

inline ll mul(ll a,ll b){
    return (a*b)%MOD;
}

ll p1[MAXN],q1[MAXN];

void solve(){
    pow_2[0] = 1;
    for(int i=1;i<MAXN;++i){
        pow_2[i] = (pow_2[i-1]*2)%MOD;
    }
    for(int i=0;i<MAXN;++i){
        rev_pow2[i] = rev(pow_2[i]);
    }
    int n,m,k;
    cin >> n >>m >> k;
    for(int i=1;i<=n;++i){
        cin >> val[i];
    }
    for(int i=1;i<=k;++i){
        cin >> s[i];
    }
    for(int i=1;i<=m;++i){
        int a,b;
        cin >> a >> b;
        g[a].pb(b);
        g[b].pb(a);
    }

    for(int i=1;i<=k;++i){
        used[s[i]] = 1;
    }
    for(int i=1;i<=k;++i){
        int v = s[i];
        if(check[v])
            continue;
        check[v] = 1;
        for(int to:g[v]){
            if(!used[to]){
                if(val[to]==0)
                    continue;
                cout << -1<<"\n";
                return;
            }
            if(sz(g[to])>=block){
                to_big[v].pb(to);
            }
        }
    }

    memset(used,0,sizeof used);
    for(int i=1;i<=n;++i){
        p1[i] = 0;
        q1[i] = 1;
    }

    for(int i=1;i<=k;++i){
        int v = s[i];
        for(int e=0;e<sz(to_big[v]);++e){
            int to = to_big[v][e];
            cnt[v]+=inc[to] - add_last[v][e];
            add_last[v][e] = inc[to];
        }
        if(sz(g[v])>=block){ // BIG
            inc[v]++;
        } else{ // SMALL
            for(int to:g[v]){
                cnt[to]++;
            }
        }
        used[v]++;
        if(cnt[v]==0){
            continue;
        }
        dout << i <<" "<<cnt[v]<<endl;
        ll p2 = mul(cnt[v],val[v]);
        ll q2 = pow_2[used[v]-1];
        dout <<"add "<<p2 <<" "<<q2<<endl;
        add(p1[v],q1[v],p2,q2);

        cnt[v] = 0;
    }

    ll p = 0, q = 1;
    for(int i=1;i<=n;++i){
        add(p,q,p1[i],q1[i]);
        p1[i] = 0;
        q1[i] = 1;
    }
    dout << "First "<<endl;
    dout << p <<" "<<q<<endl;
    dout << mul(p,rev(q))<<endl;

    for(int i=1;i<=k;++i){
        int v = s[i];
        for(int e=0;e<sz(to_big[v]);++e){
            int to = to_big[v][e];
            cnt[v]+=inc[to] - add_last[v][e];
            add_last[v][e] = inc[to];
        }
        if(sz(g[v])>=block){ // BIG
            inc[v]++;
        } else{ // SMALL
            for(int to:g[v]){
                cnt[to]++;
            }
        }
        used[v]++;
        if(cnt[v]==0){
            continue;
        }
        dout << i <<" "<<cnt[v]<<endl;
        ll p2 = mul(cnt[v],val[v]);
        ll q2 = pow_2[used[v]-1];
        add(p1[v],q1[v],p2,q2);

        cnt[v] = 0;
    }

    for(int i=1;i<=n;++i){
        ll b1 = mul(p1[i],rev(q1[i]));
        ll k = rev_pow2[used[i]/2];

        ll p2 = b1;
        ll q2 = (1 - k + MOD)%MOD;
        add(p,q,p2,q2);
    }
    dout << p <<" "<<q<<endl;
    cout << mul(p,rev(q))<<endl;











}

signed main(){
    #ifdef zxc
        debug = 1;
        freopen("input.txt","r",stdin);
    #endif // zxc

    int t=1;
     ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    while(t--)
        solve();
}