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#include <bits/stdc++.h>

using namespace std;

#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define ALL(x) begin(x), end(x)
#define SZ(x) (int)(x).size()
#define st first
#define nd second
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<ll> vl;

#ifdef LOCAL
#define DTP(x, y)                                    \
    auto operator<<(auto &o, auto a)->decltype(y, o) \
    {                                                \
        o << "(";                                    \
        x;                                           \
        return o << ")";                             \
    }
DTP(o << a.first << ", " << a.second, a.second);
DTP(for (auto i : a) o << i << ", ", ALL(a));
void dump(auto... x) { ((cerr << x << ", "), ...) << '\n'; }
#define debug(x...) cerr << setw(4) << __LINE__ << ":[" #x "]: ", dump(x)
#else
#define debug(...) 42
#endif

void solve()
{
    int n, q;
    cin >> n >> q;
    set<string> A, B;
    string S;
    cin >> S;
    for (int i = 1; i < (1 << n); i++)
    {
        string temp = "";
        for (int j = 0; j < n; j++)
            if ((1 << j) & i)
                temp += S[j];
        // debug(temp);
        if (!A.insert(temp).second)
            B.insert(temp);
    }
    cout << B.size() << endl;
    while (q--)
    {
        int a;
        char b;
        cin >> a >> b;
        S[a - 1] = b;
        A.clear();
        B.clear();
        for (int i = 1; i < (1 << n); i++)
        {
            string temp = "";
            for (int j = 0; j < n; j++)
                if ((1 << j) & i)
                    temp += S[j];
            // debug(temp);
            if (!A.insert(temp).second)
                B.insert(temp);
        }
        cout << B.size() << endl;
    }
}

main()
{
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);

    int Z = 1;
    // cin >> Z;
    while (Z--)
        solve();
}