#include <iostream>
using namespace std;
int main() {
// write your code here......
long long int n;
cin>>n;
if(n<=1){
return 0;
}
for(int i=1;i<=n/2;i++){
for(int j=1;j<=i;j++){
if(i*j==n){
cout<<"不是质数"<<endl;
return 0;
}
}
}
cout<<"是质数"<<endl;
return 0;
}