#include<bits/stdc++.h> using namespace std; bool sushu(int n) { if(n1)return false; //1²»ÊÇËØÊý for(int i=2;i*i<=n;i++)//¼ìÑé1µ½x¿ª¸ùºÅ¼´¿É { if(n%i0) return false;//±»iÈ¡ÓàΪ0£¬²»ÊÇËØÊý } return true; }//¶¨ÒåËØÊýº¯Êý int main() { int n; cin>>n; if(sushu(n)) { cout<<"yes"; } else cout<<"no"; return 0; }