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

#define all(v) v.begin(), v.end()

using LL = long long;

int main() {
  cin.tie (nullptr) -> ios_base :: sync_with_stdio (false);

  int tests;
  cin >> tests;
  while (tests--) {
    int n;
    cin >> n;
    cout << --n / 2 << '\n';
  }

  return 0;
}