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

int main()
{
    int n, k; cin >> n >> k;
    vector <int> A(n+1);
    int utidijas = 0;
    for(int i = 1; i <= n; i++)
    {
        cin >> A[i];
        if(A[i] == 1) utidijas += 1;
    }
    int ans = 0;
    ans += (utidijas - k + 1) * (k-1);
    ans += (k-1) * (k-2) / 2;
    if(ans < 0) cout << 0;
    else cout << ans;
    return 0;
}