#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define sp " "
#define YES cout << "YES" << endl
#define NO cout << "NO" << endl
#define Yes cout << "Yes" << endl
#define No cout << "No" << endl
#define yes cout << "yes" << endl
#define no cout << "no" << endl

void messi()
{
    int n;
    cin >> n;
    if (n % 2 == 1)
    {
        cout << n / 2 << endl;
    }
    else
    {
        cout << n / 2 - 1 << endl;
    }
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(NULL);
    ll tc = 1;
    cin >> tc;
    while (tc--)
    {
        messi();
    }
    return 0;
}