#include <bits/stdc++.h>

using namespace std;
#define int long long

// 快速幂 (a^k)%p
int qmi(int a, int k, int p) {
    int res = 1;
    while (k) {
        if (k & 1) res = res * a % p;
        a = a * a % p;
        k >>= 1;
    }
    return res;
}

signed main() {
    int n;
    cin >> n;
    while (n--) {
        int a, p;
        cin >> a >> p;
        if (a % p == 0)
            puts("impossible"); // 不互质
        else
            printf("%lld\n", qmi(a, p - 2, p));
    }
}