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#include <bits/stdc++.h>

using namespace std;
using ll = long long;

#define int ll

const int MAX_N = 2e5+2;
const int M = 1e9+7;
int tab[3][3][MAX_N];
int two[MAX_N];
const int inv_3 = 333333336;

int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);

  int pow = 1;
  for (int k = 0; k < MAX_N; k++) {
    int neg = 1;
    if (k % 2) neg = -1;
    tab[0][0][k] = (2*neg + pow) * inv_3;
    tab[0][0][k] %= M;
    tab[0][1][k] = (-neg + pow) * inv_3;
    tab[0][1][k] %= M;
    tab[0][2][k] = tab[0][1][k];
    tab[1][0][k] = 2*(pow - neg) * inv_3;
    tab[1][0][k] %= M;
    tab[1][1][k] = (neg + (pow*2)%M) * inv_3;
    tab[1][1][k] %= M;
    tab[1][2][k] = (neg + (pow*2)%M) * inv_3;
    tab[1][2][k] %= M;
    tab[2][0][k] = 2*(neg + (pow*2)%M) * inv_3;
    tab[2][0][k] %= M;
    tab[2][1][k] = (-neg + (pow*4)%M) * inv_3;
    tab[2][1][k] %= M;
    tab[2][2][k] = (-neg + (pow*4)%M) * inv_3;
    tab[2][2][k] %= M;
    pow *= 8; 
    pow %= M;
  }
  two[0] = 1;
  for (int k = 1; k < MAX_N; k++) {
    two[k] = two[k-1] * 2;
    two[k] %= M;
  }

  int N, q;
  cin >> N >> q;
  string s;
  cin >> s;
  int cev = 0, cod = 0, zev = 0, zod = 0, n = 0;
  for (int i = 0; i < N; i++) {
    if (s[i] == 'C') {
      if (i % 2 == 0) cev++;
      else cod++;
    }
    else if (s[i] == 'Z') {
      if (i % 2 == 0) zev++;
      else zod++;
    }
    else {
      n++;
    }
  }
  do {
    int c = cod + cev, z = zod + zev;
    int d = abs(c-z)%3;
    int bad = 0;
    int n_ = n;
    bad = tab[n_%3][d%3][n_/3];
    if (N % 2 != 0 && N > 1) {
      if (cev == 0 && zod == 0) bad++;
      if (cod == 0 && zev == 0) bad++;
    }
    cout << (two[n] - bad+M)%M << '\n';
    if (q) {
      int i;
      char c;
      cin >> i >> c;
      i--;
      if (c == 'C') {
        if (i % 2 == 0) cev++;
        else cod++;
      }
      else if (c == 'Z') {
        if (i % 2 == 0) zev++;
        else zod++;
      }
      else {
        n++;
      }
      if (s[i] == 'C') {
        if (i % 2 == 0) cev--;
        else cod--;
      }
      else if (s[i] == 'Z') {
        if (i % 2 == 0) zev--;
        else zod--;
      }
      else {
        n--;
      }
      s[i] = c;
    }
  }
  while (q--);

  return 0;
}