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#include <iostream>
#include <algorithm>
#include <cmath>

typedef long long int ll;
int n,m,k;
int r;

const int N = 200000, M = 200000, K = 500000;
const int LGN = 20;
int lgn;
ll g[N+1];

struct node
{
 node *left;
 node *right;
 node *parent;
 int v;
 int pre;
 int post;
 int s;

};
node z[2*N+2];

node *p[LGN+4][2*N+2];
node *namieszalem[2*N+2];

node *root;

void dfs(node *u,int &pre,int &post)
{
    u->pre = ++pre;
    u->s ++;

    if(u->left)
    {
        dfs(u->left,pre,post);
        u->s += u->left->s;
        dfs(u->right,pre,post);
        u->s += u->right->s;
    }
    p[0][u-z] = u->parent;
    u->post = ++post;
}

void dfs()
{
    r++;
    root = z+r;
    z[r].pre = 1;
    z[r].s = 1;
    int pre = 1;
    int post = 0;
    p[0][r] = root;
    for(int i=1;i<r;i++)
        if(!z[i].parent)
        {
            z[i].parent = root;
            dfs(z+i,pre,post);
            z[r].s += z[i].s;
        }
    z[r].post = ++post;
}

bool dzieciok(node*u,node*v)
{
    return u->pre>=v->pre && u->pre<v->pre+v->s;
}

node *lca(node*u,node*v)
{
    if(dzieciok(u,v))
        return v;
    if(dzieciok(v,u))
        return u;
    int j = lgn;
    while(j>=0)
    {
        if(dzieciok(v,p[j][u-z]))
            j --;
        else
            u = p[j][u-z];
    }
    return p[0][u-z];
}

struct reakcja
{
    int a,b;
    int rank;
};

reakcja R[K+1];

bool cmp(const reakcja&a,const reakcja&b)
{
    return a.rank < b.rank;
}

int main()
{
 std::cin.sync_with_stdio(false);
 std::cin >> n >> m >> k;
 lgn = int(std::log(2.0*n)/std::log(2.0)+2);
 for(int i=1;i<=n;i++)
 {
  std::cin >> g[i];
  z[i].v = i;
  namieszalem[i] = z+i;
 }
 r = n;
 for(int i=1;i<=m;i++)
 {
  int a,b;
  std::cin >> a >> b;
  r++;
  z[r].left = namieszalem[a];
  z[r].right = namieszalem[b];
  namieszalem[a]->parent = z+r;
  namieszalem[b]->parent = z+r;
  z[r].v = r;
  namieszalem[b] = z+r;
 }

 dfs();
 for(int i=1;i<=LGN;i++)
     for(int j=1;j<=r;j++)
         p[i][j] = p[i-1][p[i-1][j]-z];

 for(int i=0;i<k;i++)
 {
     std::cin >> R[i].a >> R[i].b;
     R[i].rank = lca(z+R[i].a,z+R[i].b)->post;
 }

 std::stable_sort(R,R+k,cmp);
 ll osad = 0;
 for(int i=0;i<k;i++)
 {
     if(R[i].rank==r)
         continue;
     ll u = std::min(g[R[i].a],g[R[i].b]);
     osad += 2*u;
     g[R[i].a] -= u;
     g[R[i].b] -= u;
 }
 std::cout << osad << std::endl;
 return 0;
}