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// {{{
#define _USE_MATH_DEFINES
#include <bits/stdc++.h>

#define each(...)    for (auto& __VA_ARGS__)
#define rep(i, b, e) for (int i = (b); i <= (e); i++)
#define rev(i, b, e) for (int i = (e); i >= (b); i--)
#define mp make_pair
#define mt make_tuple
#define x first
#define y second
#define pb push_back
#define all(x) (x).begin(), (x).end()
#ifdef SPONGE
#define dbg(f, ...) fprintf(stderr, "\033[1;33m" f "\033[0m", ##__VA_ARGS__)
#else
#define dbg(...) 1
#endif
#define tC template<class

using namespace std;

tC T> using V = vector<T>;
tC T1, class T2> using P = pair<T1,T2>;
tC T, class C=greater<T>> using PQ = priority_queue<T,V<T>,C>;

using ll = long long;
using ld = long double;
using ul = unsigned long long;
using pii = P<int,int>;
using pll = P<ll,ll>;
using pld = P<ld,ld>;
using vi = V<int>;
using vll = V<ll>;
using vld = V<ld>;
using vb = V<bool>;
using vs = V<string>;
using vpii = V<pii>;
using vpll = V<pll>;
using vpld = V<pld>;

tC T> int sz(const T& a) { return (int)a.size(); }
tC T> bool amin(T& a, T b) { return b < a ? a = b, 1 : 0; }
tC T> bool amax(T& a, T b) { return b > a ? a = b, 1 : 0; }

const size_t rseed = 4488;
// chrono::high_resolution_clock::now().time_since_epoch().count();
mt19937 rnd(rseed);
tC T> T rand(T lo, T hi) { return uniform_int_distribution<T>{lo,hi}(rnd); }

const int oo = 1e9 + 1;
const ll OO = 1e18 + 1;

namespace { void solve(); }
// }}}

int main()
{
  int t = 1;
  // scanf("%d", &t);
  rep(i, 1, t) {
    // printf("Case #%d: ", i);
    solve();
  }
}

namespace {

const int N = 2e5 + 17;
const int M = 1e9 + 7;

int n, q;
char s[N];

int a[N], ile[3], ile_mod_2[3][2], r[N][3], pot[N];

int int_of_kolor(char c)
{
  if (c == 'N') {
    return 0;
  }
  else if (c == 'C') {
    return 1;
  }
  else /* 'Z' */ {
    return 2;
  }
}

void pytaj()
{
  if (n == 1) {
    if (a[1] == 0) printf("2\n");
    else printf("1\n");
  }
  else {
    int xd = 2 * (ile[1] - (ile[2] % 3) + ile[0] + 3) % 3;
    //dbg("xd=%d\n", xd);

    int odp = (pot[ile[0]] - r[ile[0]][xd] + M) % M;
    //dbg("odp1=%d\tpot[2]=%d ile[0]=%d r[0][0]=%d\n", odp, pot[2], ile[0], r[2][0]);

    if (ile_mod_2[1][0] == 0 && ile_mod_2[2][1] == 0 && ile_mod_2[0][0] % 3 != xd) {
      odp = (odp + M - 1) % M;
    }
    if (ile_mod_2[1][1] == 0 && ile_mod_2[2][0] == 0 && ile_mod_2[0][1] % 3 != xd) {
      odp = (odp + M - 1) % M;
    }

    printf("%d\n", odp);
  }
}

void solve()
{
  scanf("%d %d %s", &n, &q, &s[1]);

  r[0][0] = 1;
  pot[0] = 1;
  rep(i, 1, n) {
    r[i][0] = (r[i - 1][0] + r[i - 1][2]) % M;
    r[i][1] = (r[i - 1][1] + r[i - 1][0]) % M;
    r[i][2] = (r[i - 1][2] + r[i - 1][1]) % M;
    pot[i] = 2 * pot[i - 1] % M;
  }

  rep(i, 1, n) {
    a[i] = int_of_kolor(s[i]);
    ile[a[i]]++;
    ile_mod_2[a[i]][i % 2]++;
  }

  pytaj();

  while (q--) {
    int i;
    char t[10];
    scanf("%d %s", &i, &t[1]);

    ile[a[i]]--;
    ile_mod_2[a[i]][i % 2]--;

    s[i] = t[1];
    a[i] = int_of_kolor(s[i]);
    ile[a[i]]++;
    ile_mod_2[a[i]][i % 2]++;

    pytaj();
  }
}

}