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#include <cstdio>
#include <algorithm>
#include <cstring>
using namespace std;

#define VDEBUG(...) 
#define DEBUG(...) 
//#define DEBUG(...) fprintf(stderr, __VA_ARGS__); fflush(stderr)
//#define VDEBUG(...) fprintf(stderr, __VA_ARGS__); fflush(stderr)
//#define SETIMPL unordered_set<int>
//#define SETIMPL set<int>
#define SETIMPL hash_table

#define MAXN 200007
#define MAXM 200007
#define MAXK 500007
#define INF 1000000000

#define HASH(x, nbuckets) (x * 1442968193) & (nbuckets - 1)

class hash_table {
public:
	int nbits, nbuckets, nvalues, v;
	int *buckets;
	int *values;
	int *next;
	
	hash_table() {
		v = 0;
		nvalues = 0;
		nbuckets = 0;
		values = NULL;
		next = NULL;
		buckets = NULL;
		grow();
	}
	
	~hash_table() {
		free(buckets);
		free(values);
		free(next);
	}
	
	void grow() {
		nvalues = nvalues ? 2 * nvalues : 16;
		values = (int*) realloc(values, nvalues * sizeof(int));
		next = (int*) realloc(next, nvalues * sizeof(int));
		
		nbuckets = nbuckets ? 2 * nbuckets : 16;
		buckets = (int*) realloc(buckets, nbuckets * sizeof(int));
		memset(buckets, 0, nbuckets * sizeof(int));
		for (int i = 1; i <= v; i++) {
			int b = HASH(values[i], nbuckets);
			next[i] = buckets[b];
			buckets[b] = i;
		}
		for (int i = 0; i < nbuckets; i++) {
			int j = buckets[i];
			while (j) {
				j = next[j];
			}
		}
	}
	
	void insert(int val) {
		if (v == nvalues - 1)
			grow();
		v++;
		int b = HASH(val, nbuckets);
		values[v] = val;
		next[v] = buckets[b];
		buckets[b] = v;
	}
	
	bool find(int val) {
		int b = HASH(val, nbuckets);
		int i = buckets[b];
		while (i) {
			if (values[i] == val) {
				return true;
			}
			i = next[i];
		}
		return false;
	}
	
	int size() {
		return v;
	}
};


int N, M, K, Rcnt;

int G[MAXN];
int A[MAXM], B[MAXM];
SETIMPL *F[MAXN];

struct reaction {
	int c, d;
	int id;
} R[MAXK], Rfinal[MAXK];

bool rcmp(const reaction &a, const reaction &b) {
	return a.id < b.id;
}

int main() {
	int i;
	long long cnt = 0;
	
	scanf("%d %d %d", &N, &M, &K);
	for (i = 0; i < N; i++)
		scanf("%d", &G[i+1]);
	for (i = 0; i < M; i++)
		scanf("%d %d", &A[i], &B[i]);
	for (i = 0; i < K; i++) {
		scanf("%d %d", &R[i].c, &R[i].d);
		R[i].id = i;
		if (!F[R[i].c])
			F[R[i].c] = new SETIMPL();
		if (!F[R[i].d])
			F[R[i].d] = new SETIMPL();
		F[R[i].c]->insert(i);
		F[R[i].d]->insert(i);
	}
	
	Rcnt = 0;
	for (i = 0; i < M; i++) {
		SETIMPL *from, *to;
		VDEBUG("[%d %d]\n", A[i], B[i]);
		if (!F[A[i]])
			continue;
		if (!F[B[i]]) {
			F[B[i]] = F[A[i]];
			continue;
		}
		if (F[A[i]]->size() < F[B[i]]->size()) {
			from = F[A[i]];
			to = F[B[i]];
		} else {
			from = F[B[i]];
			to = F[A[i]];
		}
		
		VDEBUG("(%d: %d %d)\n", i, from->size(), to->size());
		cnt += from->size();
		int Rstart = Rcnt;
#if 0
		SETIMPL::iterator it, hint = to->begin();;
		for (it = from->begin(); it != from->end(); it++) {
			pair<SETIMPL::iterator,bool> r = to->insert(*it);
			if (r.second == false) {
				Rfinal[Rcnt++] = R[from->values[j]];
				to->erase(r.first);
			}
		}
#else
		for (int j = 1; j <= from->v; j++) {
			if (to->find(from->values[j])) {
				Rfinal[Rcnt++] = R[from->values[j]];
			} else {
				to->insert(from->values[j]);
			}
		}
#endif
		if (Rcnt - Rstart > 1)
			sort(Rfinal + Rstart, Rfinal + Rcnt, rcmp); 
		delete from;
		F[A[i]] = NULL;
		F[B[i]] = to;
	}
	long long ret = 0;
	for (i = 0; i < Rcnt; i++) {
		int osad;
		VDEBUG("%d %d %d %d\n", Rfinal[i].c, Rfinal[i].d, Rfinal[i].t, Rfinal[i].id);
		osad = min(G[Rfinal[i].c], G[Rfinal[i].d]);
		ret += (long long) osad;
		G[Rfinal[i].c] -= osad;
		G[Rfinal[i].d] -= osad;
	}
	DEBUG("cnt = %lld\n", cnt);
	printf("%lld\n", 2LL*ret);
	
	return 0;
}