1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef pair<int, int> pii;

#define FOR(x, b, e) for(int x = (b); x <= (e); ++(x))
#define FORD(x, b, e) for(int x = (b); x >= (e); --(x))
#define REP(x, n) for(int x = 0; x < (n); ++x)
#define ALL(c) (c).begin(), (c).end()
#define SIZE(x) ((int)(x).size())
#define FOREACH(a, b) for (auto&a : (b))
#define PB push_back
#define PF push_front
#define ST first
#define ND second
#define DBG(vari) cerr<<#vari<<" = "<<(vari)<<endl

template <typename T>
std::ostream& operator<<(std::ostream &output, const vector<T> &vec)
{
    output << "[";
    FOREACH(x, vec) output << x << ", ";
    output << "]";
    return output;
}

template <typename T, typename U>
std::ostream& operator<<(std::ostream &output, const pair<T,U> &p)
{
    output << "(";
    output << p.ST << ", " << p.ND;
    output << ")";
    return output;
}

const int MOD = 998'244'353;

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);


  int n, q; cin >> n >> q;
  string s; cin >> s;

  //string s = "10100101";
  int m = SIZE(s);
  FOR(i, 1, SIZE(s)-1) {
    if (s[i] == s[i-1]) {
      m--; 
    }
  }

  s = "$" + s + "$";

  vi fib(50'010);
  fib[0] = 1;
  fib[1] = 1;
  FOR(i, 2, SIZE(fib)-1) {
    fib[i] = (fib[i-1] + fib[i-2]) % MOD;
  }

  if (m == 1) {
    cout << 2 << endl;
  }
  else
  {
    int comb = (fib[m+1]+1) % MOD;
    cout << comb << endl;
  }

  while (q--) {
    int p;
    char z;
    cin >> p >> z;
    
    if (s[p] != z) {
      if (s[p-1] == '$' || s[p+1] == '$') {
        if (s[p] == s[p-1] || s[p] == s[p+1])
          m++;
        else
          m--;
      }
      else
      {
        if (s[p] == s[p-1] && s[p] == s[p+1])
          m += 2;
        else if (s[p] != s[p-1] && s[p] != s[p+1])
          m -= 2;
      }

    }

    s[p] = z;

    if (m == 1) {
      cout << 2 << endl;
    }
    else
    {
      cout << (fib[m+1]+1) % MOD << endl;
    }

    //DBG(s);
    //DBG(m);
  }
}