#include <bits/stdc++.h>

using namespace std;

#define fst(t) std::get<0>(t)
#define snd(t) std::get<1>(t)
#define thd(t) std::get<2>(t)
#define unless(p) if(!(p))
#define until(p) while(!(p))

using ll = long long;
using P = std::tuple<int,int>;

const int dx[8] = {-1, 1, 0, 0, -1, -1, 1, 1}, dy[8] = {0, 0, -1, 1, -1, 1, -1, 1};

int N, M;
std::string S;
std::vector<P> G;
int cntP[100100], cntA[100100];

int main(){
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    std::cin >> N >> M;
    std::cin >> S;

    for(int i=0;i<M;++i){
        int u, v;
        std::cin >> u >> v;

        --u; --v;

        if(S[u] > S[v]){
            std::swap(u, v);
        }

        G.emplace_back(u, v);

        if(S[u] == 'A'){
            cntA[v] += 1;
        }

        if(S[v] == 'P'){
            cntP[u] += 1;
        }
    }

    ll res = 0;
    for(auto &p : G){
        int u, v;
        std::tie(u, v) = p;

        if(S[u] == 'C' && S[v] == 'D'){
            res += 1ll * cntP[v] * cntA[u];
        }
    }

    std::cout << res << std::endl;
}