#include<iostream>
#include<algorithm>
using namespace std;
typedef long long LL;
LL qmi(int a, int b, int p)
{
LL res=1%p;
while(b)
{
if(b & 1) res = res * a %p;
a = a * (LL) a % p;
b>>=1;
}
return res;
}
int main()
{
int n;
cin>>n;
while(n--)
{
int a,p;
scanf("%d%d",&a,&p);
if(a % p == 0) cout<<"impossible"<<endl;
else cout<<qmi(a,p-2,p)<<endl;
}
return 0;
}