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#include <algorithm>
#include <vector>
#include <cstdio>
#include <unordered_map>


struct Vertex
{
	Vertex()
		: tree(-1), level(0), to(-1)
	{}

	int tree; // nr drzewa do ktorego wierzcholek nalezy
	int level; // poziom w danym drzewie
	int to; // krawedzie od wierzcholka
	std::vector<int> from; // krawedzie do wierzcholka
};
std::vector<Vertex> vertices(200001);


struct TreeData
{
	TreeData(int _uniq = -1)
		: root(-1), index(0), unique_id(_uniq)
	{}

	void prepare(int _ver); // przygotowuje drzewo, szuka roota --- O(m), m - ilosc wierzcholkow
	void createEulerTour(int _ver, int _depth); // tworzy sciezke po drzewie --- O(2*m)
	void prepareRMQ(); // przygotowuje rmq --- O(2 * m * log(m))

	int LCA(int _v1, int _v2); // odpowiada na najmniejsza wartosc w przedziale

	// ---
	int root, index, unique_id;
	std::vector<std::vector<int>> acount; // licznik pozycji przodkow
	std::vector<std::vector<int>> rmq; // range minumum query - dla szybkiego wyznaczania LCA
	std::vector<int> euler;
	std::unordered_map<int, int> mapping; // mapuje wierzcholki na wewnetrzna notacje
	std::unordered_map<int, int> inv_map;
};

void TreeData::prepare(int _ver)
{
	// szukaj roota
	root = _ver;
	while (vertices[root].to != -1) {
		root = vertices[root].to;
	}
	// -----
	index = 0;
	createEulerTour(root, 0);
	prepareRMQ();
}

void TreeData::createEulerTour(int _ver, int _depth)
{
	int tidx = index;
	vertices[_ver].level = _depth;
	vertices[_ver].tree = unique_id;
	mapping[_ver] = tidx;
	inv_map[tidx] = _ver;
	euler.push_back(tidx);
	while (tidx >= acount.size()) {
		acount.emplace_back(std::vector<int>());
	}
	acount[tidx].emplace_back(euler.size() - 1);
	for (auto &v : vertices[_ver].from) {
		++index;
		createEulerTour(v, _depth + 1);
		euler.push_back(tidx);
		acount[tidx].emplace_back(euler.size() - 1);
	}
}

void TreeData::prepareRMQ()
{
	int lg = (int)(std::log2(euler.size()));
	rmq.resize(euler.size());
	for (int i = 0; i < rmq.size(); ++i) {
		rmq[i].resize(lg + 1);
		rmq[i][0] = euler[i];
	}
	for (int j = 1; 1 << j < rmq.size(); ++j) {
		for (int i = 0; i + (1 << j) - 1 < rmq.size(); ++i) {
			rmq[i][j] = std::min(rmq[i][j-1], rmq[i+(1<<(j-1))][j-1]);
		}
	}
}

int TreeData::LCA(int _v1, int _v2)
{
	_v1 = mapping[_v1]; _v2 = mapping[_v2];
	_v1 = acount[_v1][0]; _v2 = acount[_v2][0];
	if (_v1 > _v2) {
		std::swap(_v1, _v2);
	}
	int k = (int)(std::log2(_v2 - _v1 + 1));
	int tmp = 1 << k;
	return std::min(rmq[_v1][k], rmq[_v2-tmp+1][k]);
}

// -----

struct Query
{
	int treeId;
	int lca;
	int level;
	int anc;
	int c, d;
};

bool operator<(const Query &_q1, const Query &_q2)
{
	return (_q1.treeId < _q2.treeId) || (!(_q1.treeId > _q2.treeId) && ((_q1.level > _q2.level) || (!(_q1.level < _q2.level) && ((_q1.lca < _q2.lca) || (!(_q1.lca > _q2.lca) && (_q1.anc < _q2.anc))))));
}


int main()
{
	int n, m, k;
	int treeCounter = 0;
	scanf("%d%d%d", &n, &m, &k);
	std::vector<long long> sub(n+1);
	std::vector<TreeData> trees;
	for (int i = 0; i < n; ++i) {
		scanf("%d", &sub[i+1]);
	}
	for (int i = 0; i < m; ++i) {
		int a, b;
		scanf("%d%d", &a, &b);
		vertices[a].to = b;
		vertices[b].from.emplace_back(a);
	}
	for (int i = 1; i <= n; ++i) {
		if (vertices[i].tree == -1) {
			trees.emplace_back(TreeData(treeCounter++));
			trees.back().prepare(i);
		}
	}
	std::vector<Query> queries;
	for (int i = 0; i < k; ++i) {
		int c, d;
		scanf("%d%d", &c, &d);
		if (vertices[c].tree == vertices[d].tree) {
			int tid = vertices[c].tree;
			queries.emplace_back(Query{});
			queries.back().treeId = vertices[c].tree;
			queries.back().lca = trees[tid].LCA(c, d);
			queries.back().level = vertices[trees[tid].inv_map[queries.back().lca]].level;
			int far = std::max(trees[tid].acount[trees[tid].mapping[c]][0], trees[tid].acount[trees[tid].mapping[d]][0]);
			queries.back().anc = std::lower_bound(trees[tid].acount[queries.back().lca].begin(), trees[tid].acount[queries.back().lca].end(), far) - trees[tid].acount[queries.back().lca].begin();		
			queries.back().c = c;
			queries.back().d = d;
		}
	}
	std::stable_sort(queries.begin(), queries.end());
	long long res = 0;
	for (auto &it : queries) {
		long long m = std::min(sub[it.c], sub[it.d]);
		res += m + m;
		sub[it.c] -= m;
		sub[it.d] -= m;
	}
	
	printf("%lld\n", res);
	return 0;
}