#include<bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i=a;i<b;i++)
#define rrep(i,a,b) for(int i=a;i>=b;i--)
#define fore(i,a) for(auto& i:a)
#define ff first 
#define ss second 
#define all(a) begin(a),end(a)
#define allr(a) rbegin(a),rend(a)
#define pb push_back
using ll =long long;
using pii=pair<int,int>;
using pll=pair<ll,ll>;
using vi=vector<int>;
using vll=vector<ll>;
template<class T> inline bool chmin(T& a,T b){return a>b?a=b,1:0;}
template<class T> inline bool chmax(T& a,T b){return a<b?a=b,1:0;}

const int INFI=numeric_limits<int>::max()/2;
const ll INFL=numeric_limits<ll>::max()/2;

long long sqrtll(long long x) {
    assert(x >= 0);
    long long rev = sqrt(x);
    while(rev * rev > x) --rev;
    while((rev+1) * (rev+1)<=x) ++rev;
    return rev;
}

void solve(){
    const ll D=1e6;
    ll n;cin>>n;
    ll root=sqrtll(n);
    for(ll d=0;d<(1<<20);d++){
        ll i=(d^root);
        ll j=n^i;
        if(i*i<=j&&j<(i+1)*(i+1)){
            cout<<j<<'\n';
            return;
        }
    }
    cout<<-1<<'\n';
}

int main(){
    cin.tie(0)->sync_with_stdio(0);
    /*
    ll n;cin>>n;
    ll ans{};
    map<ll,ll> mp;
    for(ll i=0;i<=2*n;i++){
        ll tmp=(sqrtll(i)^i);
        chmax(ans,abs(tmp-i));
        mp[i]=tmp;
    }
    auto out=[](ll x){
        for(int i=0;i<40;i++){
            cout<<((x>>i)&1);
        }
        cout<<endl;
    };
    fore(i,mp){
        cout<<'N'<<endl;
        out(sqrtll(i.ff));
        out(sqrtll(i.ss));
    }
    cout<<endl;*/
    
    int t;
    cin>>t;
    
    while(t--)solve();
    return 0;
}
/*
高々2個っぽい
*/