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#include <cstdio>
#include <vector>
#include <cmath>
#include <algorithm>
#define PB push_back
#define ST first
#define ND second
using namespace std;
typedef pair<int, int> PII;
typedef long long LL;

const int MX_N = 200010;

LL res;
int n, m, k, size, korzen, ct, a, b; // long longi!!!
int w[MX_N], akt[MX_N], p[20][2*MX_N], pre[2*MX_N], post[2*MX_N], r[2*MX_N];
bool vis[2*MX_N];

vector<int> v[2*MX_N];
vector<PII> vlca[2*MX_N];

void dfs(int x, int rep)
{
	ct++;
	pre[x] = ct;
	vis[x] = true;
	r[x] = rep;
	for (int i = 0; i < (int)v[x].size(); ++i)
		dfs(v[x][i], rep);
	
	ct++;
	post[x] = ct;
}

bool potomek(int u, int v)
{
	return ((pre[u] > pre[v]) && (post[u] < post[v]));
}

int sufit(double x)
{
	if ((x - (int)x) == 0)
		return (int)x;
	else
		return (int)x + 1;
}

int lca(int u, int v)
{
	if (potomek(u, v))
		return v;
	else if (potomek(v, u))
		return u;
	else
	{
		int i = u;
		int j = sufit(log(n) / log(2));
		while (j >= 0)
		{
			if (potomek(v, p[j][i]))
				j--;
			else
				i = p[j][i];
		}
		return p[0][i];
	}
}

void dfs2(int x)
{
	vis[x] = true;
	for (int i = 0; i < (int)v[x].size(); ++i)
		dfs2(v[x][i]);
		
	for (int i = 0; i < (int)vlca[x].size(); ++i)
	{
		LL wag = min(w[vlca[x][i].ST], w[vlca[x][i].ND]);
		w[vlca[x][i].ST] -= wag;
		w[vlca[x][i].ND] -= wag;
		res += 2*wag;
	}
}
int main ()
{
	scanf ("%d%d%d", &n, &m, &k);
	for (int i = 1; i <= n; ++i) // Waga
	{
		scanf ("%d", &w[i]);
		akt[i] = i;
	}
	
	size = n;
	for (int i = 0; i < m; ++i) // Przelania
	{
		scanf ("%d%d", &a, &b);
		size++;
		p[0][akt[a]] = p[0][akt[b]] = size;
		v[size].PB(akt[a]); 
		v[size].PB(akt[b]);
		akt[b] = size;
	}
	
	korzen = size;
	for (int i = korzen; i >= 1; --i)
	{
		if (!vis[i])
		{
			p[0][i] = i;
			dfs(i, i);
		}
	}
	
	int LOGN = sufit(log(n) / log(2));
	for(int i = 1; i <= LOGN; ++i) // p[i][j] = wierzcholek u taki, ze d(u, j) = 2^i
		for(int j = korzen; j >= 1; --j)
			p[i][j] = p[i-1][p[i-1][j]];
			
	for (int i = 0; i < k; ++i)
	{
		scanf ("%d%d", &a, &b);
		if (r[a] == r[b])
			vlca[lca(a, b)].PB(PII(a, b));
	}
	
	for (int i = 0; i <= korzen; ++i)
		vis[i] = false;
		
	for (int i = korzen; i >= 1; --i)
	{
		if (!vis[i])
			dfs2(i);
	}
	printf ("%lld", res);
}