#include "bits/stdc++.h"
using namespace std;
#define ll long long int
#define rep(i,n) for( int i = 0; i < n; i++ )
#define rrep(i,n) for( int i = n; i >= 0; i-- )
#define REP(i,s,t) for( int i = s; i <= t; i++ )
#define RREP(i,s,t) for( int i = s; i >= t; i-- )
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define INF 2000000000
#define mod 1000000007
#define INF2 1000000000000000000
vector<int> v[100010];
string S;
char s[3] = {'D', 'C', 'A'};
int ans = 0;

void search(int a, int depth) {
    if (depth == 3) {
        ans++;
        return;
    }
    for(auto e : v[a]){
        if (S[e] == s[depth]) search(e, depth + 1);
    }
}

int main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N, M; cin >> N >> M;
    cin >> S;
    rep(i, M) {
        int a, b; cin >> a >> b;
        a--; b--;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    rep(i, N) {
        if (S[i] == 'P') search(i, 0);
    }
    cout << ans << endl;

    return 0;
}