#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

int main() {
    pair<int, char> p[3];
    string s = "ABC";
    for (int i = 0; i < 3; i++) {
        int a;
        cin >> a;
        p[i] = { a, s[i] };
    }
    sort(p, p+3);
    reverse(p, p+3);
    for (auto x : p) cout << x.second << endl;
    return 0;
}