#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;
#define pb push_back
#define all(v) v.begin(),v.end()
#define endl '\n'
#define int long long
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL) 
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;

const int mxn = 1e6 + 123;
int a[mxn],b[mxn];
void solve(){
	int n;
	cin>>n;
	cout<<(n-1)/2<<endl;
} 
signed main() {
    fastio;
    int t = 1;
    cin >> t;
    while (t--) {
        solve();
    }
}