#include <stdio.h>

int main() {
    int input;
    scanf("%i", &input);
    printf("Your input was: %i\n", input);

    char letter;
    if ((input/10) >= 9) {
        letter = 'A';
    } else if ((input/10) >= 8) {
        letter = 'B';
    } else if ((input/10) >= 7) {
        letter = 'C';
    } else if ((input/10) >= 6) {
        letter = 'D';
    } else {
        letter = 'F';
    }

    printf("Your letter grade is %c\n", letter);
    return 0;
}