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// Witold Milewski
// PA 2025
#include <bits/stdc++.h>
// #define int long long
#define i128 __int128_t
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;
#define FOR(i, a, b) for(int i=a; i<=b; ++i)
#define FORB(i, b, a) for(int i=b; i>=a; --i)
#define sz(A) (int)(A.size())
#define ll long long
#define eb emplace_back
#define pb push_back
#define pi pair<int, int>
#define f first
#define s second
#define rs resize
#define V vector
const int p=998244353, p1=11, m1=1e9+7, maxn=5e4+7;

int n, q;
V<int> A, pot1;

void solve() {
  gp_hash_table<int, int> licz;
  FOR(m, 1, (1<<n)-1) {
    int h1=0;
    int ktora=1;
    FOR(i, 0, n-1) {
      if((m&(1<<i))==0) continue;
      h1=(0ll+h1+(1ll*pot1[ktora]*A[i+1]))%m1;
      ++ktora;
    }
    licz[h1]++;
  }

  int odp=0;
  for(auto &[str, ile] : licz) if(ile>=2) odp=(odp+1)%p;
  cout << odp << '\n';
}

signed main() {
  cin.tie(0) -> ios_base::sync_with_stdio(0);
  pot1.rs(maxn);
  pot1[0]=1;
  FOR(i, 1, maxn-1) pot1[i]=(pot1[i-1]*p1)%m1;

  cin >> n >> q;
  string str;
  cin >> str;
  A.rs(n+1);
  FOR(i, 1, n) A[i]=str[i-1]-'a'+1;

  solve();

  int idx;
  char lit;
  while(q--) {
    cin >> idx >> lit;
    A[idx]=lit-'a'+1;
    solve();
  }
}