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#include <bits/stdc++.h>

using namespace std;

char cs[50050];
char seq[50050];

unordered_map<string, int> counts;

void f(int p, int c, int n) {
    if(p == n) {
        string s(seq, c);
        counts[s]++;
        return;
    }

    seq[c++] = cs[p];
    for(int i = p + 1; i <= n; i++) {
        f(i, c, n);
    }
    seq[c--] = 0;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int n, q;
    cin >> n >> q;
    cin >> cs;

    for(int i = 0; i < n; i++) {
        f(i, 0, n);
    }

    int r = 0;
    for(auto i: counts) {
        r += i.second > 1;
    }
    cout << r << "\n";

    while(q--) {
        int p;
        char z;
        cin >> p >> z;
        cs[--p] = z;
        counts.clear();

        for(int i = 0; i < n; i++) {
            f(i, 0, n);
        }

        int r = 0;
        for(auto i: counts) {
            r += i.second > 1;
        }
        cout << r << "\n";

    }

    return 0;
}