#include <iostream>
#include <string>

#define ll long long
using namespace std;

ll ss(int a,int b, int c){
    ll res = 1;
    while(b){
        if(b & 1) res = res * a % c;
        a = a * (ll) a % c;
        b >>= 1;
    }
    return res;
}

void solve(){
    int a,b;
    scanf("%d%d",&a,&b);
    if(a % b == 0) printf("impossible\n");
    else printf("%lld\n",ss(a,b - 2,b));
    return;
}

int main(){
    int t;
    scanf("%d",&t);
    while(t --)
    solve();
    return 0;
}