#include <bits/stdc++.h>
using namespace std; 
using ll = long long;
#include <math.h> 

bool is_prime(ll num){
    if (num < 2) return false;
    else if (num == 2) return true;
    else if (num % 2 == 0) return false; // 偶数はあらかじめ除く

    double sqrtNum = sqrt(num);
    for (int i = 3; i <= sqrtNum; i += 2)
    {
        if (num % i == 0)
        {
            // 素数ではない
            return false;
        }
    }

    // 素数である
    return true;
}

int main(){
    int t; cin >> t;
    while(t--){
        ll a, p; cin >> a >> p;
        if(is_prime(p)){
            ll fact[p+1];
            fact[1] = a % p;
            int tmp;
            for(int i = 2; i <= p; i++){
                fact[i] = fact[i-1] * a % p;
                //cout << i << " " <<  fact[i] << endl;
                if(fact[i] == fact[1]){
                    tmp = i - 1;
                    break;
                }
            }
            cout << fact[tmp] << endl;
        }
        else{
            cout << -1 << endl;
        }
    }
}