#include <iostream> #include <cmath> using namespace std; int main() { int n; while (cin >> n) { // 注意 while 处理多个 case // cout << a + b << endl; if (n <= 0 || n == 1) { cout << "no" << endl; continue; } int bound = sqrt(n); bool flag = true; for (int i = 2; i <= bound; i++) { if (n % i == 0) { flag = false; break; } } if (flag == false)cout << "no" << endl; else cout << "yes" << endl; } } // 64 位输出请用 printf("%lld")