#include <bits/stdc++.h>
using namespace std; 
using ll = long long;
const int MAX = 5e6+2;
ll a;
int p;
ll fact[MAX];

bool is_prime(ll num){
    if (num < 2) return false;
    else if (num == 2) return true;
    else if (num % 2 == 0) return false; 
    double sqrtNum = sqrt(num);
    for (int i = 3; i <= sqrtNum; i += 2){
        if (num % i == 0){
            return false;
        }
    }
    return true;
}

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