#include <bits/stdc++.h>
using namespace std;
int a[1000005];
int main() {
    int n, m;
    cin >> n >> m;
    for (int i = 0; i < n; ++ i)
    {
        int x;
        cin >> x;
        ++ a[x];
    }
    int sol = 0, s = 0, res = 0;
    sort (a, a + m + 1, greater<int>());
    for (int i = 0; i <= m; ++ i)
    {
        int r = min (a[i], s);
        a[i] -= r;
        s -= r;
        sol += r * 2;
        sol += min (a[i], res);
        a[i] -= min (a[i], res);
        s += a[i];
        res = sol;
    }
    cout << sol;
}