#include <iostream>
using namespace std;
int main(){
   int a;
   cin>>a;
   if(a >= 90){
   	  cout<<"yes"<<endl;
   }
   return 0;
}

/**************************************************************
	Problem: 1301
	User: admin
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/