#include <bits/stdc++.h>
using namespace std;

long long gcd(long long x, long long y)
{
    if (y == 0)
        return x;
    return gcd(y, x % y);
}

long long lcm(long long x, long long y)
{
    if (x == 0 || y == 0)
        return 0;
    return x / gcd(x, y) * y;
}

int main()
{
    vector<pair<int, int>> HW(3);
    map<pair<int, int>, char> mp;
    for (int i = 0; i < 3; i++)
    {
        int H, W;
        cin >> H >> W;
        HW[i] = pair<int, int>(H, W);
        mp[pair<int, int>(H, W)] = 'A' + i;
    }
    sort(HW.begin(), HW.end(), ::greater<pair<int, int>>());
    for (int i = 0; i < 2; i++)
    {
        if (HW[i].first == HW[i + 1].first && HW[i].second > HW[i + 1].second)
            swap(HW[i], HW[i + 1]);
    }
    for (int i = 0; i < 3; i++)
    {
        cout << mp[HW[i]] << endl;
    }
}