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

typedef long long ll;
typedef double dl;

#define endl "\n"
#define optimize() ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define fraction() cout.unsetf(ios::floatfield); cout.precision(10); cout.setf(ios::fixed,ios::floatfield);

int main()
{
    optimize();

    int t;

    cin >> t;

    while(t--){
        int n;

        cin >> n;

        int ans;

        if(n % 2 == 0)   ans = n/2 - 1;
        else ans = n / 2;


        cout << ans << endl;
    }

    return 0;
}