#include <iostream> using namespace std; int main(){ int n, a = 0; cin >> n; if (n <= 1) { cout << "NO"; return 0; } for(int i = 2; i <= n; i++){ if(n % i == 0){ a++; if (a > 1) break; } } if(a == 1){ cout << "Yes"; } else{ cout << "No"; } return 0; }