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#include <bits/stdc++.h>
//#include <emmintrin.h>

using namespace std;

#define FORE(it,c)  for(__typeof((c).begin()) it = (c).begin(); it != (c).end(); ++it)
#define FOR(i,a,b)  for(int i=(a);i<(b);++i)
#define REP(i,a)    FOR(i,0,a)
#define ZERO(m)    memset(m,0,sizeof(m))
#define ALL(x)      x.begin(),x.end()
#define PB          push_back
#define S          size()
#define LL          long long
#define ULL        unsigned long long
#define LD          long double
#define MP          make_pair
#define X          first
#define Y          second
#define VC          vector
#define PII        pair <int, int>
#define VI          VC < int >
#define VPII          VC < PII >
#define VVI        VC < VI >
#define VD          VC < double >
#define VVD        VC < VD >
#define VS          VC < string >
#define DB(a)      cerr << #a << ": " << (a) << endl;

template<class T> void print(VC < T > v) {cerr << "[";if (v.S) cerr << v[0];FOR(i, 1, v.S) cerr << ", " << v[i];cerr << "]\n";}
template<class T> string i2s(T x) {ostringstream o; o << x; return o.str(); }
VS splt(string s, char c = ' ') {VS all; int p = 0, np; while (np = s.find(c, p), np >= 0) {if (np != p) all.PB(s.substr(p, np - p)); p = np + 1;} if (p < s.S) all.PB(s.substr(p)); return all;}

const int MAX_N = 201000;
const int MAX_K = 501000;
const int LOG_MAX_N = 20;

LL RV = 0;
int N, M, K;

int G[MAX_N];
int TP[MAX_N];
int TL[MAX_N];
VI TC[MAX_N];
int TO[MAX_N];
VPII TR[MAX_N];
PII R[MAX_K];

int LCA[MAX_N][LOG_MAX_N];

void simulate(int p) {
	for (int x : TC[p]) simulate(x);
	
	if (p == 0) return;
	
	sort(ALL(TR[p]));
	for (PII r : TR[p]) {
		int x = r.Y;
		int a = min(G[R[x].X], G[R[x].Y]);
		RV += 2 * a;
		G[R[x].X] -= a;
		G[R[x].Y] -= a;
	}
}

void calcTL(int p, int l = 0) {
	TL[p] = l;
	for (int x : TC[p]) calcTL(x, l + 1);
}


void solve() {
	//compute TL
	calcTL(0);
	
	//LCA preprocess
	memset(LCA, -1, sizeof(LCA));
	REP(i, N + 1) LCA[i][0] = TP[i];
	FOR(j, 1, LOG_MAX_N) REP(i, N + 1) if (LCA[i][j-1] != -1) LCA[i][j] = LCA[LCA[i][j-1]][j-1];
	
	//LCA 
	REP(k, K) {
		int a = R[k].X;
		int b = R[k].Y;
		
		if (TL[a] < TL[b]) swap(a, b);
		
		
		if (TL[a] == TL[b]) b = TP[b];
		
		for (int i = LOG_MAX_N - 1; i >= 0; i--)
			if (TL[a] - (1 << i) > TL[b])
				a = LCA[a][i];
				
		if (TP[a] != b) {
			a = TP[a];
			for (int i = LOG_MAX_N - 1; i >= 0; i--)
				if (LCA[a][i] != LCA[b][i]) {
					a = LCA[a][i];
					b = LCA[b][i];
				}
			TR[TP[a]].PB(MP(max(TO[a], TO[b]), k));
		} else {
			TR[TP[a]].PB(MP(TO[a], k));
		}
	}
	
	
	
	//simulate
	simulate(0);
}

void add(int a, int b) {
	TP[a] = b;
	TC[b].PB(a);
	TO[a] = TC[b].S;
}

int main() {
	scanf("%d%d%d", &N, &M, &K);
	REP(i, N) scanf("%d",&G[i+1]);
	memset(TP, -1, sizeof(TP));
	REP(i, M) {
		int a, b;
		scanf("%d%d", &a, &b);
		add(a, b);
	}
	FOR(i, 1, N+1) if (TP[i] == -1) add(i, 0);
	REP(i, K) scanf("%d%d", &R[i].X, &R[i].Y);
	
	solve();
	
	cout << RV << endl;
	
	return 0;
}