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#include <stdio.h>
#include <algorithm>
#include <vector>

using namespace std;

using namespace std;

typedef long long LL;

const int MaxN = 200005,
          MaxV = 400005,
          LogMaxV = 22,
          MaxM = 200005,
          MaxK = 500005,
          ErrNoLCA = -31337;


int N, M, K, V;
int mass[MaxN]; // masy
int destination[LogMaxV][MaxV]; // [0][v] - rodzic; potem 2^k to [k][v]
int depth[MaxV]; // glebokosc wierzcholka w drzewie
int actualLoc[MaxN]; // aktualne polozenie i-tej probowki
vector<int> children[MaxV]; // dzieci (<= 2) wierzcholka

int reactC[MaxK], reactD[MaxK];
vector<int> meeting[MaxV]; // numery par reagujacych substancji w momencie


void input(){
	scanf("%d%d%d", &N, &M, &K);
	V = N;
	
	for(int i = 0; i < N; i++){
		scanf("%d", &mass[i]);
		actualLoc[i] = i;
	}
	
	for(int i = 0; i <= 2*N; i++)
		destination[0][i] = i;
	
	for(int i = 0; i < M; i++){
		int a, b;
		scanf("%d%d", &a, &b);
		a--; b--;
		
		// tworzymy przejscie do nowej probowki z probowek zaw. 'a' i 'b'
		destination[0][actualLoc[a]] = V;
		destination[0][actualLoc[b]] = V;
		//destination[0][V] = V;
		children[V].push_back(actualLoc[a]);
		children[V].push_back(actualLoc[b]);
		//printf("%d => %d %d\n", V+1, actualLoc[a]+1, actualLoc[b]+1);
		actualLoc[b] = (V++);
	}
	
	for(int i = 0; i < K; i++){
		scanf("%d%d", &reactC[i], &reactD[i]);
		reactC[i]--; reactD[i]--;
	}
}

/** OBSLUGA LCA **/
int logv;

void process_lca(){
	logv = 0;
	int pwr = 1;
	
	while(pwr < V){ pwr *= 2; logv++; }
	
	// przesuwamy
	for(int i = 1; i <= logv; i++){
		//printf("%d :", i);
		for(int w = 0; w < V; w++){
			destination[i][w] = destination[i-1][destination[i-1][w]];
			//printf(" %d", destination[i][w]+1);
		}
		//printf("\n");
	}
}

bool vis[MaxV];

int dfs(int v){
	if(vis[v])
		return depth[v];
	
	vis[v] = true;
	if(destination[0][v] == v) return (depth[v] = 0);
	
	return (depth[v] = dfs(destination[0][v]) + 1);
}

void process_depth(){
	fill(vis, vis+V, false);
	for(int i = 0; i < V; i++){
		if(!vis[i]){
			dfs(i);
		}
	}
}

int push(int v, int num){ // przesuwa 'v' o 'num' do gory
	for(int i = 0; i <= logv; i++){
		if(num & (1<<i))
			v = destination[i][v];
	}
	return v;
}

int get_lca(int u, int v){
	// brak LCA
	if(destination[logv][u] != destination[logv][v])
		return ErrNoLCA;
	
	//printf("get_lca(%d, %d)", u+1, v+1);
	
	int depthU = depth[u], depthV = depth[v];
	if(depthU < depthV)
		v = push(v, depthV-depthU);
	else
		u = push(u, depthU-depthV);
	
	//printf(" = get_lca(%d,%d)\n", u+1, v+1);
	
	if(u == v) return u;
	
	for(int i = logv; i >= 0; i--){
		int newV = destination[i][v],
		    newU = destination[i][u];
		
		if(newV != newU){
			v = newV; u = newU;
		}
	}
	return destination[0][v];
}
/** KONIEC OBSLUGI LCA **/


LL result = 0;


void dfs_pour(int w){
	for(int s: children[w]){
		dfs_pour(s);
	}
	
	for(int numReact: meeting[w]){
		int c = reactC[numReact], d = reactD[numReact];
		
		int decr = min(mass[c], mass[d]);
		result += 2*decr;
		mass[c] -= decr;
		mass[d] -= decr;
		//printf("Connecting %d with %d, decrease = %d\n", c+1, d+1, decr);
	}
}

int main(){
	input();
	process_lca();
	process_depth();
	
	// przetwarzamy reagenty
	for(int i = 0; i < K; i++){
		int res = get_lca(reactC[i], reactD[i]);
		
		//printf("%d %d => %d\n", reactC[i]+1, reactD[i]+1, res+1);
		
		if(res != ErrNoLCA){ // dodajemy mozliwa reakcje do wierzcholka
			meeting[res].push_back(i);
		}
	}
	
	// DFS-ujemy
	fill(vis, vis+V, false);
	for(int i = 0; i < V; i++){
		if(!vis[i] && destination[0][i] == i){ // nieodwiedzony korzen
			dfs_pour(i);
		}
	}
	
	printf("%lld\n", result);
}