#include <bits/stdc++.h>

using namespace std;

#define REP(i, n) for(int i = 0; i < n; i++)
#define FORR(i, m, n) for(int i = m; i >= n; i--)
#define VSORT(v) sort(v.begin(), v.end())

int main() {
    vector<pair<int, int>> vp;
    REP(i, 3) {
        int h;
        cin >> h;
        vp.push_back(make_pair(h, i));
    }

    VSORT(vp);
    FORR(i, 2, 0) {
        cout << (char) ('A' + vp[i].second) << endl;
    }
    return 0;
}