#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "algo/debug.h"
#else
#define debug(...) 42
#endif

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int t;
  cin >> t;
  while(t--) {
    int n;
    cin >> n;
    if(n%2==0){
      cout << n/2-1 <<"\n";
    }else{
      cout << (n+1)/2-1<<"\n";
    }
  }
}