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#include <bits/stdc++.h>
using namespace std;
#define rep(a, b) for (int a = 0; a < (b); a++)
#define rep1(a, b) for (int a = 1; a <= (b); a++)
#define all(x) (x).begin(), (x).end()
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
const int MOD = 1e9 + 7;

#define LOCAL false

int n, q;
string str;

int ans() {
    map<string, int> subseq;
    rep(msk, 1<<n) {
        string sub;
        rep(i, n) if (msk&(1<<i)) sub += str[i];
        subseq[sub]++;
    }
    int mult = 0;
    for (auto [s, cnt]: subseq) {
        if (s.size()>0 && cnt>1) mult++;
    }
    return mult;
}

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    if (LOCAL) {
        ignore=freopen("io/in", "r", stdin);
        ignore=freopen("io/out", "w", stdout);
    }

    cin >> n >> q;
    cin >> str;

    cout << ans() << "\n";
    int idx;
    char c;
    rep(i, q) {
        cin >> idx >> c;
        str[idx-1] = c;
        cout << ans() << "\n";
    }

    return 0;
}