// ?
// F(k) = k^floor(sqrt(k))
//
// k - sqrt(k) <= F(k) <= k + sqrt(k)
//
//

use std::io::Write;
use std::collections::*;

type Map<K, V> = BTreeMap<K, V>;
type Set<T> = BTreeSet<T>;
type Deque<T> = VecDeque<T>;

fn run() {
    input! {
        t: usize,
        ask: [u64; t],
    }
    for n in ask {
        if let Some(a) = solve(n) {
            println!("{}", a);
        } else {
            println!("-1");
        }
    }
}

fn solve(n: u64) -> Option<u64> {
    let mut sq = 0;
    for i in 0..100000 {
        if (sq + 1) * (sq + 1) <= i {
            sq += 1;
        }
        if i ^ sq == n {
            return Some(i);
        }
    }
    if n <= 100 {
        return None;
    }
    let sq = kth_root(n, 2);
    for sq in sq.saturating_sub(1000)..=(sq + 1000) {
        if kth_root(n ^ sq, 2) == sq {
            return Some(n ^ sq);
        }
    }
    None
}

fn main() {
    run();
}

// ---------- begin input macro ----------
// reference: https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
#[macro_export]
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        let s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

#[macro_export]
macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};
    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

#[macro_export]
macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };
    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };
    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };
    ($iter:expr, bytes) => {
        read_value!($iter, String).bytes().collect::<Vec<u8>>()
    };
    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };
    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}
// ---------- end input macro ----------
// floor(a^(1/k))
pub fn kth_root(a: u64, k: u64) -> u64 {
    assert!(k > 0);
    if a == 0 {
        return 0;
    }
    if k >= 64 {
        return 1;
    }
    if k == 1 {
        return a;
    }
    let mut v = ((a as f64).ln() / k as f64).exp().round() as u64;
    if v.checked_pow(k as u32).map_or(true, |p| p > a) {
        v -= 1;
    }
    v
}