#include <bits/stdc++.h>
using namespace std;
#define int long long
#define enl "\n"
#define all(x) x.begin(), x.end()
#define FAST ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
const int N = 2e5 + 19;

void solve() 
{
    int n;
    cin >> n;

    cout << (n - 1) / 2 << enl; 

}

signed main()
{
    FAST
    
    int T = 1;
    cin >> T;
    while(T--) {
        solve();
    }
    return 0;
    
}