/*
    BISMILLAHIR RAHMANIR RAHIM
*/
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define endl '\n'
void solve()
{
    int n;cin>>n;
    cout<<(n-1)/2<<endl;
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int t=1;
    cin>>t;
    while(t--)
    {
      solve();
    }
    return 0;
}