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/*	Arek Wróbel - skater
 *
 *	Zadanie: Fiolki
 *	Konkurs: PA2014, runda 5B
 */
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <vector>
#include <map>
using namespace std;
typedef long long LL;
typedef pair<int, int> PII;
typedef vector<int> VI;
#define REP(I, N) for(int I=0; I<(N); ++I)
#define FOR(I, M, N) for(int I=(M); I<=(N); ++I)
#define FORD(I, M, N) for(int I=(M); I>=(N); --I)
#define FOREACH(IT, CON) for(__typeof(CON.begin()) IT=CON.begin(); IT!=CON.end(); ++IT)
#define ST first
#define ND second
#define MP make_pair
#define PB push_back
const int INF=1000000000;
const LL INFLL=1000000000000000000LL;

//struct Subst {
//	map<int, LL> s;
//};
typedef map<int, LL> Subst;

int n, m, k;
Subst subst[200009];

PII kroki[200009];
PII reakcje[500009];

LL osad = 0;

void pP(pair<int, LL> p) {
	printf("  (%d: %lld)\n", p.ST, p.ND);
}

int main()
{
	//wej
	scanf("%d%d%d", &n, &m, &k);
	REP(i, n) {
		LL g;
		scanf("%lld", &g);
		subst[i][i]=g;
	}
	REP(i, m) {
		int a, b;
		scanf("%d%d", &a, &b);
		kroki[i] = MP(a-1, b-1);
	}
	REP(i, k) {
		int c, d;
		scanf("%d%d", &c, &d);
		reakcje[i] = MP(c-1, d-1);
	}
	//prog
	REP(I, m){
		int A = kroki[I].ST, B = kroki[I].ND;
//		printf("%d: %d %d\n", I, A, B);
//		printf(" prob %d\n", A); FOREACH(it, subst[A]) pP(*it);
//		printf(" prob %d\n", B); FOREACH(it, subst[B]) pP(*it);
		if (subst[A].size() > subst[B].size())
			swap(subst[A], subst[B]);
		FOREACH(it, subst[A])
			subst[B].insert(*it);
		subst[A].clear();
		REP(i, k){
			int a = reakcje[i].ST, b = reakcje[i].ND;
			Subst::iterator ia, ib;
			ia = subst[B].find(a);
			if (ia == subst[B].end()) continue;
			ib = subst[B].find(b);
			if (ib == subst[B].end()) continue;
			int x = min((*ia).ND, (*ib).ND);
			(*ia).ND -= x;
			(*ib).ND -= x;
			osad += 2*x;
			if ((*ia).ND == 0)
				subst[B].erase(a);
			if ((*ib).ND == 0)
				subst[B].erase(b);
		}
	}
	//wyj
	printf("%lld\n", osad);
	return 0;
}