// I AM A MUSLIM

#include "bits/stdc++.h"

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")

#define fastIO std::ios::sync_with_stdio(0);std::cin.tie(0)
#define ll long long int
#define flush fflush(stdout)
#define bl printf("\n")
#define yn(a, b) printf("%s\n", a >= b ? "Yes":"No")
// #define int ll

using pii = std::pair<int,int>;

const int MOD = 1000000007;
// const int MOD = 998244353;
const int mxN = 100100;

signed main() {
    // fastIO;
    int testCases=1;
    scanf("%d",&testCases);
    // std::cin>>testCases;
    
    for (int TC = 1; TC <= testCases; TC++) {
        int N;
        scanf("%d",&N);
        int ans = N/2;
        if (N%2 == 0) ans--;
        printf("%d\n",ans);
        
    }
    
    return 0;
}

/*

*/