#include <bits/stdc++.h>
using namespace std;
#include<atcoder/all>
// using mint = atcoder::modint998244353;
using ld = long double;
#define fi first
#define se second
#define all(x) x.begin(),x.end()
#define rep(i,n) for(int i=0;i<(int)(n);++i)
template<typename T>bool chmin(T&a,T b){return b<a?(a=b,1):0;}
template<typename T>bool chmax(T&a,T b){return b>a?(a=b,1):0;}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    int T;
    cin>>T;
    while(T--){
        int N;
        cin>>N;
        if(__popcount(N)==1){
            cout<<-1<<"\n";
            continue;
        }
        int mae=-1;
        int ans=2e9;
        rep(i,30){
            if((N>>i)&1){
                if(mae!=-1)chmin(ans, (1<<i)-mae);
                mae=1<<i;
            }
        }
        cout<<ans<<"\n";
    }
}