#include using namespace std; #define ALL(x) x.begin(),x.end() #define rep(i,n) for(int i=0;i<(n);i++) #define debug(v) cout<<#v<<":";for(auto x:v){cout<bool chmax(T &a,const T &b){if(abool chmin(T &a,const T &b){if(b ostream &operator<<(ostream &os,const pair&p){ os< ostream &operator<<(ostream &os,const vector&v){ for(int i=0;i<(int)v.size();i++) os< sieve(int n){ vector ret(n+1,true); ret[0]=false; if(n>0) ret[1]=false; for(int i=2;i*i<=n;i++){ if(!ret[i]) continue; for(int j=i*2;j<=n;j+=i) ret[j]=false; } return ret; } signed main(){ auto v=sieve(5000010); int q;cin>>q; while(q--){ int a,p;cin>>a>>p; if(!v[p]){ cout<<-1<