use std::io::*;

fn mod_pow(mut x: u64, mut e: u64, m: u64) -> u64 {
    let mut res = 1;
    while e > 0 {
        if e & 1 == 1 {
            res = res * x % m;
        }
        x = x * x % m;
        e >>= 1;
    }
    res
}

fn main() {
    let mut s: String = String::new();
    std::io::stdin().read_to_string(&mut s).ok();
    let mut itr = s.trim().split_whitespace();
    let t: usize = itr.next().unwrap().parse().unwrap();
    const MAX: usize = 5000005;
    let mut is_prime: Vec<bool> = vec![true; MAX];
    is_prime[0] = false;
    is_prime[1] = false;
    for i in 2..MAX {
        if is_prime[i] {
            let mut j = i * 2;
            while j < MAX {
                is_prime[j] = false;
                j += i;
            }
        }
    }

    let mut out = Vec::new();
    for _ in 0..t {
        let a: u64 = itr.next().unwrap().parse().unwrap();
        let p: u64 = itr.next().unwrap().parse().unwrap();

        //
        if is_prime[p as usize] {
            // a^(p!) mod p
            // a^(p - 1) = 1 mod p
            // p * (p -1) * (p -2) * ...Copy
            // x^p == x mod p
            writeln!(out, "{}", mod_pow(a % p, (p - 1) / 2 + 1, p)).ok();
        } else {
            writeln!(out, "-1").ok();
        }
    }
    stdout().write_all(&out).unwrap();
}