#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;
}