1#include <iostream>
2using namespace std;
3 
4int main() {
5    int score = 75;
6    if (score >= 90) {
7        cout << "A" << endl;
8    } else if (score >= 80) {
9        cout << "B" << endl;
10    } else if (score >= 70) {
11        cout << "C" << endl;
12    } else {
13        cout << "F" << endl;
14    }
15    return 0;
16}