/// wykorzystane zadanie komiwojażer z 9. oi

#include <iostream>
#include <cstdio>
#include <vector>
#include <cmath>
#include<algorithm>
#define maxN 200005
#define maxO 500005

using namespace std;

int currTree, Tin[maxN], Tout[maxN], Depth[maxN], D[20][maxN], mxd=0, tim, fiol[maxN], tab[maxN], pary[2][maxN], tree[maxN];
bool vst[maxN];
vector <int> G[maxN];
vector< pair< int, pair<int, int> > > osad;

void dfs (int a) {
    vst[a]=1;
    tree[a] = currTree;
    tim++;
    Tin[a]=tim;
    for (int i=0; i<G[a].size(); i++)
        if (Depth [G[a][i]]==0) {
            Depth [G[a][i]]=Depth[a]+1;
            mxd=max(mxd, Depth [G[a][i]]);
            D[0][G[a][i]]=a;
            dfs(G[a][i]);
        }
    Tout[a]=tim;
}

bool potomek (int a, int b) {
    return (Tin[a]<=Tin[b] && Tout[a]>=Tout[b]);
}

bool cmp(pair<int, pair<int, int> > a,pair<int, pair<int, int> > b ){
    return (a.first > b.first );
}

int LCA (int a, int b) {
    if (potomek (a,b)) return a;
    else if (potomek (b, a) ) return b;
    int i=a, j = mxd;
    while(j>=0){
        if(potomek(b, D[j][i])) j--;
        else i=D[j][i];
    }
    return D[0][i];
}

int main () {
    int n, m, k;
    scanf ("%d%d%d", &n, &m, &k);
    for(int i=1; i<=n; ++i){
        scanf("%d", &fiol[i]);
        tab[i]=i;
    }
    for (int i=0; i<m; i++) {
        int a, b;
        scanf ("%d%d", &a, &b);
        pary[0][i] = a;
        pary[1][i] = b;
        G[a].push_back(b);
        G[b].push_back(a);
    }

    int wsk=1;
    for(int i=m-1; i>=0; i--)
        for(int j=1; j>=0; j--)
            if(vst[pary[j][i]]==0) {
              //  printf(" - %d \n", pary[j][i] );
                currTree = pary[j][i];
                Depth[pary[j][i]] = 1;
                tree[pary[j][i]]=wsk;
                wsk++;
                dfs(pary[j][i]);
                D[0][pary[j][i]]=1;
            }

    double o=log2(mxd);
    mxd=o+1;

  //  printf("%d\n", mxd);
    for (int p=0; p<=mxd; p++)
        for (int u=1; u<=n; u++)
            D[p+1][u] = D[p][D[p][u]];

    for(int i=0; i<k; ++i) {
        int a, b;
        scanf ("%d%d", &a, &b);
        osad.push_back(make_pair(Depth[LCA(a, b)], make_pair(a, b)));
    }
    sort(osad.begin(), osad.end(), cmp);
    long long res = 0LL;
    for(int i=0; i<k; ++i){
        int a, b;
        a = osad[i].second.first;
        b = osad[i].second.second;
        if(tree[a] == tree[b]){
            int minn = min(fiol[a], fiol[b]);
            fiol[a] -= minn;
            fiol[b] -= minn;
            res += (long long) minn *2;
        }
    }
    printf("%lld", res);
    return 0;
}