#include<bits/stdc++.h>
#define fastio {ios_base::sync_with_stdio(false);cin.tie(NULL);}
#define ll   long long int
#define all(u) sort(u.begin(),u.end())
#define nxt(u) next_permutation(u.begin(),u.end())
#define rev(u) reverse(u.begin(),u.end())
#define cinv(u) for(auto &it : u) cin >> it;
#define pb push_back
#define Which would be worse
#define siz(st) st.size()
#define nl "\n"
#define yes cout<<"YES"<<"\n"
#define no cout<<"NO"<<"\n";
#define pii  pair < int , int >
#define v vector
#define For(s , e , k) for(int i = s ; i <= e ; i += k)
#define print(s , e , k , ar) for(int i = s ; i <= e ; i += k) cout << ar[i] << " \n"[i == e]
using namespace std;
//#ifndef ONLINE_JUDGE
//#include "template.h"
//#endif
const int fx[]={-1,0,1,0};
const int fy[]={0,1,0,-1};
const int sz = 2e5 + 10 ;
//cout<<"Case "<<t<<": "<<ans<<endl;
//priority_queue <ll, vector<ll>, greater<ll> > pq;//soto theke boro
//cout<<setprecision(10)<<fixed;
// ll id=lower_bound(de.begin(),de.end())-de.begin();
/*remainder extra space*/

void solve(){
      int n ;
      cin >> n ;
      int d = n / 2 ;
      if(n % 2 == 0) d--;
      cout << d << nl;




}
int main(){

     fastio;
     int T = 1;
     cin >> T;
     while(T--)
     solve();
}