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

int main(){
  int t;
  cin >> t;
  while (t--){
    ll n, k, ans = 0;
    cin >> n;
    /*vector<ll> a(n);
    for (int i = 0; i < n; i++){
      cin >> a[i];
    }*/
    cout << (n + 1) / 2 - 1 << endl;
  }
}