#include <bits/stdc++.h>
using namespace std;

struct edge {
	int t, n;
} e[20010];
long long n, m, k, v[3000], hd[10010], cnt = 0, ans = 0;

void add(int x, int y) {
	e[++cnt].t = y;
	e[cnt].n = hd[x];
	hd[x] = cnt;
}

int dfs(int x, int y, long long u, int fa) {
	bool k = 0;
	for (int i = hd[x]; i; i = e[i].n) {
		int ver = e[i].t;
		if (y == 4) {
			if (ver == 1)
				k = 1;
			continue;
		}
		if (ver == fa)
			continue;
		dfs(ver, y + 1, u + v[ver], x);
	}
	if (k == 1) {
		ans = max(ans, u);
	}
	return 0;
}

int main() {
	freopen("csp2022_holiday.in", "r", stdin);
	freopen("csp2022_holiday.out", "w", stdout);
	cin >> n >> m >> k;
	for (int i = 2; i <= n; i++) {
		cin >> v[i];
	}
	for (int i = 1; i <= m; i++) {
		int x, y;
		cin >> x >> y;
		add(x, y);
		add(y, x);
	}
	if (k == 0) {
		dfs(1, 0, 0, 1);
		cout << ans << endl;
		return 0;
	}
	return 0;
}