#include using namespace std;

int main() {

int score;
cin >> score;

if(score > 90 && score <= 100){
    cout << "优秀" << endl;
}else if(score > 80 && score <= 89){
    cout << "良" << endl;
}else if(score > 70 && score <= 79){
    cout << "中" << endl;
}else if(score > 60 && score <= 69){
    cout << "及格" << endl;
}else if(score > 0 && score <= 59){
    cout << "差" << endl;
}
else{
    cout << "成绩不合法" <<endl;
}


return 0;

}