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#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));
}
}