#include <iostream>
using namespace std;
int main() {
    int a = 10, b = 20, c = 5;
    if (a > b && a > c) {
        cout << "A";
    } else if (b > a && b > c) {
        cout << "B";
    } else if (c > a || c > b) {
        cout << "C";
    } else {
        cout << "D";
    }
    return 0;
}