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// Karol Kosinski 2025
#include <bits/stdc++.h>
#define FOR(i,a,b) for(int i=(a),_b=(b);i<_b;++i)
#define FR_(i,a,b) for(int i=(a),_b=(b);i<=_b;++i)
#define FD_(i,b,a) for(int i=(b),_a=(a);i>=_a;--i)
#define ALL(c) (c).begin(),(c).end()
#define SIZE(c) int((c).size())
#define X first
#define Y second
#define endl '\n'
#define NAM(x) #x,'=',x
using namespace std;
using LL = long long;
using ULL = unsigned long long;
using PII = pair<int, int>;
using TIII = tuple<int, int, int>;
template<class...T> void _cout(T...a){(cout<<...<<a);}

#ifndef ENABLE_DEBUG
#define DEB(k,p,f,x...)
#else
#define DEB(k,p,f,x...) {if(k)_cout("------",setw(4),__LINE__," : ",__FUNCTION__,endl);if(p)f(x);}
#endif
#define DEBF(f,x...)    DEB(1,1,f,x)
#define DEBL            DEBF(void,0)
#define DEBC(p,x...)    DEB(0,p,_cout,x)
#define DEBUG(x...)     DEBC(1,x)

constexpr int NX = 50'003;

int n, q;
ULL cnt;
string s;
bool W[NX];
map<string, int> M;

void rec(int k)
{
    if ( k == n )
    {
        string tmp;
        FOR(i,0,n) if ( W[i] ) tmp.push_back( s[i] );
        M[tmp] += 1;
        return;
    }
    rec( k+1 );
    W[k] = true;
    rec( k+1 );
    W[k] = false;
}

void iteration()
{
    cnt = 0;
    M.clear();
    rec(0);
    for ( const auto& el : M )
    {
        if ( el.Y > 1 ) ++ cnt;
    }
    cout << cnt % 998'244'353ULL << endl;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cin >> n >> q >> s;
    iteration();
    FOR(i,0,q)
    {
        int p; char c;
        cin >> p >> c;
        s[p-1] = c;
        iteration();
    }
    return 0;
}