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



int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
	
	ll tc; cin >> tc;
	while(tc--) {
		ll n; cin >> n;
		--n;
		cout << (n/2) << "\n";
	}
   
    return 0;
}