#include <bits/stdc++.h>
using namespace std;
#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it)
#define ALLOF(c) (c).begin(), (c).end()
typedef long long ll;
typedef unsigned long long ull;

#define MAX_PRIME 6000000
bool isprime[MAX_PRIME+1];
void init_prime(){
  fill(isprime, isprime+MAX_PRIME+1, true);
  isprime[0] = isprime[1] = false;
  for(int i = 2; i <= MAX_PRIME; i++) {
    if (isprime[i]) {
      for(int j = i*2; j <= MAX_PRIME; j += i)
      isprime[j] = false;
    }
  }
}

int main(){
  init_prime();
  
  int T;
  cin >> T;
  rep(t,T){
    ll A, P;
    cin >> A >> P;

    if(!isprime[P]) cout << -1 << endl;
    else{
      if(A==0) cout << 0 << endl;
      else cout << 1 << endl;
    }
  }
  
  return 0;
}