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

const int MAX = 5e6 + 7;

ll cr[MAX];

bool is_prime(ll p){
    for(int i = 2; i * i <= p; i++){
        if(p % i == 0) return false;
    }
    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;
        }
    }
}