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

enum
{
	MAX = 200010*2,
};

int vol[MAX];

std::vector<int> tree[MAX];
int find_and_union[MAX];
bool gotit[MAX];
int LCA[20][MAX*2];
int LCA_id[MAX];

int find_a_union(int x)
{
	if(find_and_union[x] == x)
		return x;
	return find_and_union[x] = find_a_union(find_and_union[x]);
}

int index = 0;

void dfs(int x, int h=0)
{
	LCA_id[x] = index;
	LCA[0][index++] = h;
	for(int i = 0; i < tree[x].size(); i++)
	{
		dfs(tree[x][i],h+1);
		LCA[0][index++] = h;
	}
}

int min(int a, int b) {return (a<b)?a:b; }

struct reaction
{
	int a, b, v, id;
} queue[500010];

bool operator<(reaction a, reaction b)
{
	if(a.v == b.v)
		return a.id < b.id;
	return a.v > b.v;
}

int main()
{
	int n, m, k; scanf("%d%d%d", &n, &m, &k);
	for(int i = 0; i <= n; i++)
		find_and_union[i] = i;
	for(int i = 1; i <= n; i++)
		scanf("%d", vol+i);
	int extent = n+1;
	for(int i = 0; i < m; i++)
	{
		int x,y; scanf("%d%d", &x, &y);
		int _x = find_a_union(x),
			_y = find_a_union(y);
		tree[extent].resize(2);
		tree[extent][0] = _x;
		tree[extent][1] = _y;
		find_and_union[_x] = extent;
		find_and_union[_y] = extent;
		find_and_union[extent] = extent;
		extent++;
	}
	for(int i = 1; i < extent; i++)
		if(!gotit[find_a_union(i)])
		{
			tree[0].push_back(find_a_union(i));
			gotit[find_a_union(i)] = 1;
		}
	dfs(0);
	for(int i = 1; (1<<i) <= index; i++)
	{
		int off = 1<<i;
		for(int j = 0; j <= index-off; j++)
			LCA[i][j] = min(LCA[i-1][j],LCA[i-1][j+(off>>1)]);
	}
	for(int i = 0; i < k; i++)
	{
		queue[i].id = i;
		scanf("%d%d", &(queue[i].a), &(queue[i].b));
		int id_a = LCA_id[queue[i].a],
			id_b = LCA_id[queue[i].b];
		if(id_a > id_b) {int c = id_a; id_a = id_b; id_b = c;}
		int off = 0;
		while(id_b - id_a + 1 >= (1<<off)) off++;
		off--;
		queue[i].v = min(LCA[off][id_a], LCA[off][id_b - (1<<off)+1]);
	}
	std::sort(queue,queue+k);
	long long res = 0;
	for(int i = 0; i < k && queue[i].v; i++)
	{
		int react = min(vol[queue[i].a],vol[queue[i].b]);
		res += react*2;
		vol[queue[i].a]-=react;
		vol[queue[i].b]-=react;
	}
	printf("%lld\n", res);
	return 0;
}