#include <iostream>
using namespace std;
int main(){
int score;
cin>>score;
if(score>=0 && score<=100){
if(score>=90)
cout<<"优秀";
else if(score>=80)
cout<<"良";
else if(score>=70)
cout<<"中";
else if(score>=60)
cout<<"及格";
else
cout<<"差";
}
else
cout<<"成绩不合法";
return 0;
}