#include <iostream>
using namespace std;

int main() {

    int score;
    cin >> score;

    // write your code here......
    if (score < 0 || score > 100) {
        cout << "成绩不合法" << endl;
        return 0;
    }

    int step = score / 10;
    char* grade = "优秀";
    switch (step) {
        case 10:
        case 9:
            grade = "优秀";
            break;
        case 8:
            grade = "良";
            break;
        case 7:
            grade = "中";
            break;
        case 6:
            grade = "及格";
            break;
        default:
            grade = "差";
    }
    cout << grade << endl;

    return 0;
}