#include <bits/stdc++.h>
using namespace std;
const int N = 50000;
bitset<N> a;
int b[N] = {0};
int res = 0;
int h;
bool check(int k)
{   int j = log2(h - k + 1);
    return pow(2, j) == (h - k + 1);
}
void solve()
{
    cin >> h;
    int *p = lower_bound(b + 1, b + 1 + res, h);
    if (*p == h)
    {
        cout << 1 << '\n';
        return;
    }
    while (1)
    {
        p--;
        if (check(*p))
        {
            if (*p)
                cout << log2(h - *p + 1) + 1 << '\n';
            else
                cout << log2(h - *p + 1) << '\n';
            return;
        }
        if (p == b)
        {
            cout << -1 << '\n';
            return;
        }
    }
}
int main()
{
    int t;
    cin >> t;
    for (int i = 2; i <= N; i++)
    {
        if (a[i] == 0)
            b[++res] = i;
        for (int j = 1; j <= res; j++)
        {
            if (b[j] * i > N)
                break;
            a[b[j] * i] = 1;
            if (i % b[j] == 0)
                break;
        }
    }
    while (t--)
    solve();
    return 0;
}

看不了测试点,不知道哪里错，求波hack家人们