/* -*- coding: utf-8 -*-
 *
 * 762.cc:  No.762 PDCAパス - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_N = 100000;
const int MOD = 1000000007;

/* typedef */

typedef long long ll;
typedef vector<int> vi;
typedef queue<int> qi;

/* global variables */

char s[MAX_N + 4];
int vids[256], vs[MAX_N], ds[MAX_N];
vi nbrs[MAX_N];
bool used[MAX_N];
qi qs[4];

/* subroutines */

/* main */

int main() {
  vids['P'] = 0, vids['D'] = 1, vids['C'] = 2, vids['A'] = 3;
  
  int n, m;
  scanf("%d%d%s", &n, &m, s);

  for (int i = 0; i < m; i++) {
    int u, v;
    scanf("%d%d", &u, &v);
    u--, v--;
    nbrs[u].push_back(v);
    nbrs[v].push_back(u);
  }

  for (int i = 0; i < n; i++)
    if ((vs[i] = vids[s[i]]) == 0)
      ds[i] = 1, used[i] = true, qs[0].push(i);

  for (int i = 0; i < 3; i++) {
    qi &q = qs[i];
    while (! q.empty()) {
      int u = q.front(); q.pop();
      vi &nbru = nbrs[u];
      for (vi::iterator vit = nbru.begin(); vit != nbru.end(); vit++) {
	int &v = *vit;
	if (vs[v] == i + 1) {
	  ds[v] = (ds[v] + ds[u]) % MOD;
	  if (! used[v]) {
	    used[v] = true;
	    qs[i + 1].push(v);
	  }
	}
      }
    }
  }

  int sum = 0;
  while (! qs[3].empty()) {
    int u = qs[3].front(); qs[3].pop();
    sum = (sum + ds[u]) % MOD;
  }

  printf("%d\n", sum);
  return 0;
}