#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll N = 2e5 + 10;
const ll MOD = 1e9 + 7;

void solve()
{
  ll n;
  cin >> n;
  n--;
  cout << (n / 2) << "\n";
}

int main()
{
  ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);

  int t;
  cin >> t;
  while(t--){
    solve();
  }
}