#include <bits/stdc++.h>

using namespace std;
const int N = 2e5 + 9;
int n, m;
char s[N];
int cnt[N];
int U[N], V[N];

vector<int> G[N];

int main() {
	freopen("1.in", "r", stdin); 
	while(~scanf("%d %d", &n, &m)) {
		for (int i = 1; i <= n; ++i)cnt[i]=0;
		scanf("%s", s+1);
		long long ans = 0;
		for (int i = 1; i <= n; ++i) G[i].clear();
		for(int i = 1; i <= m; ++i ) {
			scanf("%d %d", &U[i], &V[i]);
			G[U[i]].push_back(V[i]);
			G[V[i]].push_back(U[i]);
		}
		for (int i = 1; i <= n; ++i) {
			for (int j : G[i]) {
				if (s[j] != s[i])
					cnt[i]++;
			}
		}
		for(int i = 1; i <= m; ++i ) {
			int u = U[i], v = V[i];
			if (s[u] != s[v] ) {
				ans += 1LL * (cnt[u]- 1) * (cnt[v] - 1);
			}
				
		}
		printf("%lld\n", ans);	
	}
	
	return 0;
}