#include <iostream>
#include <algorithm>

int main() {
    using namespace std;
    int h[3];
    cin >> h[0] >> h[1] >> h[2];
    int hc[3] = {h[0], h[1], h[2]};
    sort(h, h+3, greater<int>());
    for (int i = 0; i < 3; i++) {
        if (h[i] == hc[0]) {
            cout << "A" << endl;
        } else if (h[i] == hc[1]) {
            cout << "B" << endl;
        } else {
            cout << "C" << endl;
        }
    }
}