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#include <bits/stdc++.h>
using namespace std;
const int N = 200001;
const long long M = 1e9 + 7;
int n, q, cc[2], zz[2];
long long t[N][3], p[N], nn;
string s;
char ch;

long long zle() {
  if (n == 1 || n % 2 == 0) {
    return 0;
  }

  int r = 0;

  if (cc[0] == 0 && zz[1] == 0) {
    r++;
  }

  if (cc[1] == 0 && zz[0] == 0) {
    r++;
  }

  return r;
}

void add(int i, char ch) {
  if (ch == 'N') {
    nn++;
  }
  if (ch == 'C') {
    cc[i % 2]++;
  }
  if (ch == 'Z') {
    zz[i % 2]++;
  }
}

void rem(int i, char ch) {
  if (ch == 'N') {
    nn--;
  }
  if (ch == 'C') {
    cc[i % 2]--;
  }
  if (ch == 'Z') {
    zz[i % 2]--;
  }
}

long long res() {
  int mod = 3;
  mod += (cc[0] + cc[1]) % 3;
  mod += nn % 3;
  mod -= (zz[0] + zz[1]) % 3;
  mod %= 3;
  if (mod % 2) {mod += 3;}

  return (2 * M + p[nn] - t[nn][mod / 2] - zle()) % M;
}

int main()
{
  ios_base::sync_with_stdio(0);

  cin >> n >> q >> s;

  for (int i = 0; i < s.size(); i++) {
    add(i, s[i]);
  }

  t[0][0] = 1;
  p[0] = 1;
  for (int i = 1; i <= n; i++) {
    for (int j = 0; j < 3; j++) {
      t[i][j] = t[i - 1][j] + t[i - 1][(j + 2) % 3];
      t[i][j] %= M;
    }
    p[i] = 2 * p[i - 1];
    p[i] %= M;
  }

  cout << res() << endl;

  int i;

  while (q--) {
    cin >> i >> ch;
    i--;
    rem(i, s[i]);
    add(i, ch);
    s[i] = ch;

    cout << res() << endl;
  }

  return 0;
}