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
#include <bits/stdc++.h>
using namespace std;

#define all(x) begin(x),end(x)
#define pb push_back
#define st first
#define nd second

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

const int INF = 2e9;
const ll LLINF = 2e18;

const int MOD = 998244353;

int compute(const string& s)
{
    map<string,int> cnt;
    int n=s.length();
    for(int mask=1; mask<(1<<n); ++mask)
    {
        string t;
        for(int i=0; i<n; ++i)
            if(mask&(1<<i))
                t+=s[i];
        ++cnt[t];
    }

    int res=0;
    for(auto p:cnt)
        res+=(p.nd>1);
    return res%MOD;
}

void solve()
{
    int n,q;
    cin>>n>>q;
    string s;
    cin>>s;
    int ans=compute(s);
    cout<<ans<<"\n";
    while(q--)
    {
        int p;
        char c;
        cin>>p>>c;
        if(s[p-1]!=c)
        {
            s[p-1]=c;
            ans=compute(s);
        }
        cout<<ans<<"\n";
    }
}

int main()
{
    ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
    int z=1;
    //cin>>z;
    while(z--)
        solve();
    return 0;
}