#include <bits/stdc++.h>
using namespace std;
long long gcd(long long a, long long b) { return b == 0 ? a : gcd(b, a % b); }
long long ppow(long long a, long long b, long long mod) {
  a %= mod;
  long long ans = 1 % mod;
  while (b) {
    if (b & 1) ans = (long long)ans * a % mod;
    a = (long long)a * a % mod;
    b >>= 1;
  }
  return ans;
}
long long readdd() {
  long long x = 0, f = 1;
  char c = getchar();
  while (!isdigit(c) && c != '-') c = getchar();
  if (c == '-') f = -1, c = getchar();
  while (isdigit(c)) x = x * 10 + c - '0', c = getchar();
  return f * x;
}
void printtt(long long x) {
  if (x < 0) putchar('-'), x = -x;
  if (x >= 10) printtt(x / 10);
  putchar(x % 10 + '0');
}
bool addd(long long a, long long b) { return a > b; };
signed main() {
  long long T;
  cin >> T;
  while (T--) {
    for (long long i = 1; i <= 100; i++)
      ;
    long long n;
    cin >> n;
    cout << (n - 1) / 2 << endl;
  }
  return 0;
}
