#include <bits/stdc++.h>
using namespace std;
int main()
{
int n;
cin >> n;
if(n < 2)
{
cout<<"NO"<<endl;
return 0;
}
for(int i = 2 ; i < n; i++)
{
if(n % i == 0)
{
cout<<"NO"<<endl;
return 0;
}
}
cout<<"YES"<<endl;
}
I2luY2x1ZGUgPGJpdHMvc3RkYysrLmg+CnVzaW5nIG5hbWVzcGFjZSBzdGQ7CgppbnQgbWFpbigpCnsKICBpbnQgbjsKICBjaW4gPj4gbjsKICBpZihuIDwgMikKICB7CiAgICBjb3V0PDwiTk8iPDxlbmRsOwogICAgcmV0dXJuIDA7CiAgfQogIGZvcihpbnQgaSA9IDIgOyBpIDwgbjsgaSsrKQogIHsKICAgIGlmKG4gJSBpID09IDApCiAgICB7CiAgICAgIGNvdXQ8PCJOTyI8PGVuZGw7CiAgICAgIHJldHVybiAwOwogICAgfQogIH0KICBjb3V0PDwiWUVTIjw8ZW5kbDsKfQ==