#include <vector>
#include <string>
#include <utility>
#include <tuple>
#include <iostream>
#include <algorithm>

using namespace std;
using ll = long long;
using pll = pair<ll,ll>;
using tiii = tuple<int,int,int>;
#define reps(i,s,n) for(int (i) = (s); (i) < (n); (i)++)
#define rep(i,n) reps(i,0,n)

int main(){
    vector<tiii> v(3);
    rep(i,3){
        int x,y;
        cin >> x >> y;
        v[i] = make_tuple(i,x,y);
    }
    string str = "ABC";
    sort(v.begin(),v.end(),[](const tiii& a, const tiii& b){
        return get<1>(a) == get<1>(b) ?
             get<2>(a) < get<2>(b): get<1>(a) > get<1>(b);
    });

    rep(i,3){
        cout << str[get<0>(v[i])] << endl;
    }

    return 0;
}