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#include <iostream>
#include <sstream>
#include <fstream>
#include <string>
#include <vector>
#include <queue>
#include <algorithm>
#include <map>
#include <set>

using namespace std;

typedef long long LL;

#define MAX(a, b) ((a) > (b) ? (a) : (b))
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#define ABS(val) ((val) < 0 ? -(val) : (val))

#define FOR(x, b, e) for(int x = b; x <= (e); ++x)
#define FORD(x, b, e) for(int x = b; x >= (e); --x)
#define REP(x, n) for(int x = 0; x < (n); ++x)
#define VAR(v, n) __typeof(n) v = (n)
#define ALL(c) (c).begin(), (c).end()
#define SIZE(x) ((int)(x).size())
#define FOREACH(i, c) for(VAR(i, (c).begin()); i != (c).end(); ++i)
#define PB push_back
#define ST first
#define ND second

/* Brute force! Please do not expect much :)*/
set<int> regs[200200];
int quant[200200];
int main() {
	int n, m, k;
	scanf("%d %d %d", &n, &m, &k);
	REP(i, n)
	{
		scanf("%d", &(quant[i+1]));
		regs[i+1].insert(i+1);
	}
	
	vector<pair<int, int> > pours;
	REP(i, m)
	{
		int from, to;
		scanf("%d %d", &from, &to);
		pours.PB(make_pair(from, to));
	}
	
	vector<pair<int, int> > reactions;
	REP(i, k)
	{
		int r1, r2;
		scanf("%d %d", &r1, &r2);
		reactions.PB(make_pair(r1, r2));
	}

	LL sum = 0LL;
	FOREACH(p, pours)
	{
		int from = p->first;
		int to = p->second;
		/*
		printf("pour: %d %d\n", from, to);
		printf("sizes: %d %d\n", regs[from].size(), regs[to].size());
		*/

		FOREACH(r, reactions)
		{
			int r1 = r->first;
			int r2 = r->second;

			bool f1in1 = regs[from].find(r1) != regs[from].end();
			bool f2in1 = regs[from].find(r2) != regs[from].end();
			bool f1in2 = regs[to].find(r1) != regs[to].end();
			bool f2in2 = regs[to].find(r2) != regs[to].end();
			//printf("%d %d %d %d\n", f1in1, f2in1, f1in2, f2in2);

			if((f1in1 && f2in2) || (f2in1 && f1in2))
			{
		//		printf("AAL0, %d %d; %d %d\n", r1, r2, quant[r1], quant[r2]);
				int sub = MIN(quant[r1], quant[r2]);
				sum += (LL)(2 * sub);
				quant[r1] -= sub;		
				quant[r2] -= sub;		
				
			}
		}

		regs[to].insert(ALL(regs[from]));
		
	}
	printf("%lld\n", sum);


	return 0;
}