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

typedef long long ll;
const ll md = 1e9+7;

void solve() {
   ll  n;
   cin>>n;
   cout<<(n-1)/2<<endl;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int T;
     cin >> T;
    while (T--) {
        solve();
    }

    return 0;
}