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

int main()
{
	vector<tuple<int, int, char>> a( 3 );
	for( int i = 0; i < 3; i++ ) {
		int H, W;
		cin >> H >> W;
		a[i] = make_tuple( H, W, (char)('A' + i) );
	}

	sort( a.begin(), a.end(), []( tuple<int, int, char> u, tuple<int, int, char> v )
							{
								if( get<0>( u ) > get<0>( v ) ) return true;
								else if( get<0>( u ) == get<0>( v ) ) {
									if( get<1>( u ) < get<1>( v ) ) return true;
									else return false;
								}
								else return false;
							} );
	for( auto e : a ) {
		cout << get<2>( e ) << endl;
	}
}