#include<bits/stdc++.h>
using namespace std;

int main(){
    int n;
    cin>>n;
    if(n>=60) cout<<"yes";
    else cout<<"no";
    return 0;
}

#include<bits/stdc++.h>

using namespace std;

int main(){

int a;

cin>>a;

0<=a<=100;

if(a>=60) cout<<"yes";

else cout<<"no";

return 0;

}