#include<iostream>
using namespace std; 
bool sushu(int s)
{
    int aa=1;
    while (1)
    {
        aa=aa+1;
        if(s==1)
        {
            cout << "是素数";
            break;
        }
        else if(s%aa==0&&s!=aa)
        {
            cout << "不是素数";
            break;
        }
        else if(s%aa==0&&s==aa)
        {
            cout << "是素数";
            break;
        }
        else
        {
            continue;
        }
    }
    return 0;
}
int main()
{
    int ss;
    cin >> ss;
    sushu(ss);
 
}