include

int main() {

int score; std::cin >> score;

char grade; if (score >= 90) {

grade = 'A';

} else if (score >= 80) {

grade = 'B';

} else if (score >= 70) {

grade = 'C';

} else if (score >= 60) {

grade = 'D';

} else {

grade = 'E';

}

std::cout << grade << std::endl;

return 0; }