Untitled

#include <iostream>
using namespace std;
int main()
{
	int t,n,i,a=1,b=0,j=1,o =0 ;
	cin >> t;
	for (i = 0; i < t; i++)
	{
		cin >> n;
		cout << (n - 1) / 2 << "\n";
	}



}