#include <iostream>
#include <algorithm>
#include <queue>
#include <vector>
#include <map>
#include <string>

using namespace std;

void solve();

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    solve();
}

void solve() {
    vector<pair <int, int> > v;
    for(int i = 0; i < 3; i++) {
        int tmp;
        cin >> tmp;
        v.push_back(make_pair(tmp,i));
    }
    sort(v.begin(),v.end());

    for(int i = 2; i >= 0; i--) {
        cout << (char)('A' + v.at(i).second) << endl;
    }
}