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#include <cstdio>
#include <vector>
#include <set>
#include <algorithm>

#define REP(i, n) for (int i = 0; i < (n); ++i)
#define FOR(i, a, b) for (int i = (a); i <= (b); ++i)
#define MP make_pair
#define FI first
#define SE second
#define PII pair<int, int>
#define PB push_back
#define LL long long

using namespace std;

int n, m, k;
vector<int> sizes;
vector<int> p;
vector<int> ranks;
vector<vector<PII > > r;
vector<int> parent;
vector<vector<PII > > children;
vector<int> ancestor;
vector<bool> color;
vector<int> colored;
vector<vector<PII > > meet;
vector<pair<PII, PII > > final;
vector<vector<PII > > notif; 
LL result;

// Implementation of disjoint sets and LCA (Tarjan's algo) based on Cormen - start
void makeSet(int x)
{
	p[x] = x;
	ranks[x] = 0;
}

int findSet(int x)
{
	if (x != p[x])
		p[x] = findSet(p[x]);
	return p[x];
}

void setLink(int x, int y)
{
	if (ranks[x] > ranks[y])
		p[y] = x;
	else
	{
		p[x] = y;
		if (ranks[x] == ranks[y])
			++ranks[y];
	}
}

void setUnion(int x, int y)
{
	setLink(findSet(x), findSet(y));
}

void LCA(int u)
{
	makeSet(u);
	ancestor[findSet(u)] = u;
	notif[u].clear();
	int numChildren = children[u].size();
	for (int i = 0; i < numChildren; ++i)
	{
		int v = children[u][i].FI;
		LCA(v);
		// Save reaction order
		int numMeet = meet[u].size();
		for (int j = 0; j < numMeet; ++j)
		{
			int r1 = meet[u][j].FI;
			int r2 = r[r1][meet[u][j].SE].FI;
			int reactOrder = r[r1][meet[u][j].SE].SE;
			int traverseOrder = children[u][i].SE;
			final.PB(MP(MP(traverseOrder, reactOrder), MP(r1, r2)));
		}
		meet[u].clear();
		int numNotif = notif[u].size();
		for (int j = 0; j < numNotif; ++j)
		{
			int r1 = notif[u][j].FI;
			int r2 = r[r1][notif[u][j].SE].FI;
			int reactOrder = r[r1][notif[u][j].SE].SE;
			int traverseOrder = children[u][i].SE;
			final.PB(MP(MP(traverseOrder, reactOrder), MP(r1, r2)));
		}
		notif[u].clear();
		//
		setUnion(u, v);
		ancestor[findSet(u)] = u;
	}
	color[u] = true;
	colored.PB(u);
	int numReacting = r[u].size();
	for (int i = 0; i < numReacting; ++i)
	{
		int v = r[u][i].FI;
		if (color[v])
		{
			int lca = ancestor[findSet(v)];
			meet[lca].PB(MP(u, i));
		}
		else
		{
			notif[v].PB(MP(u, i));
		}
	}
}
// Implementation of disjoint sets and LCA (Tarjan's algo) based on Cormen - end

void readInput()
{
	scanf("%d%d%d", &n, &m, &k);
	REP(i, n)
	{
		int size;
		scanf("%d", &size);
		sizes.PB(size);
	}
	children.resize(n);
	parent.resize(n, -1);
	REP(i, m)
	{
		int from;
		int	to;
		scanf("%d%d", &from, &to);
		--from;
		--to;
		children[to].PB(MP(from, i));
		parent[from] = to;
	}
	r.resize(n);
	REP(i, k)
	{
		int s1;
		int s2;
		scanf("%d%d", &s1, &s2);
		--s1;
		--s2;
		r[s1].PB(MP(s2, i));
		r[s2].PB(MP(s1, i));
	}
}

int main()
{
	readInput();

	ancestor.resize(n);
	color.resize(n);
	meet.resize(n);
	p.resize(n);
	ranks.resize(n);
	notif.resize(n);
	
	REP(i, n)
	{
		if (parent[i] == -1)
		{
			colored.clear();
			LCA(i);
			int numColored = colored.size();
			REP(j, numColored)
				color[j] = false;
		}
	}
	
	sort(final.begin(), final.end());
	int numFinal = final.size();
	REP(i, numFinal)
	{
		int r1 = final[i].SE.FI;
		int r2 = final[i].SE.SE;
		int size1 = sizes[r1];
		int size2 = sizes[r2];
		int minimum = min(size1, size2);
		sizes[r1] -= minimum;
		sizes[r2] -= minimum;
		result += (LL)(2*minimum);
	}
	
	printf("%lld\n", result);
	return 0;
}