#include <iostream>
#include <vector>
#include <algorithm>
#include <utility>
#include <functional>

#define REP(i, a, b) for (int i = int(a); i < int(b); i++)

using namespace std;

typedef long long int lli;

int main() {
    pair<int, char> H[3] = {};
    REP (i, 0, 3) {
        cin >> H[i].first;
        H[i].second = 'A' + i;
    }
    sort(begin(H), end(H), greater<pair<int,int>>());
    REP (i, 0, 3) cout << H[i].second << endl;
    return 0;
}