#include <algorithm>
#include <array>
#include <cmath>
#include <cstdio>
#include <deque>
#include <iomanip>
#include <iostream>
#include <numeric>
#include <optional>
#include <queue>
#include <sstream>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

int main() {
    vector<tuple<int32_t, int32_t, char>> xs(3);
    for (auto i = 0; i < 3; ++i) {
        int32_t h, w;
        cin >> h >> w;
        auto c = char('A' + i);
        xs[i] = {-h, w, c};
    }
    sort(xs.begin(), xs.end());
    for (auto i = 0; i < 3; ++i) {
        cout << get<2>(xs[i]) << endl;
    }
    return 0;
}