#include "bits/stdc++.h"
#define rep(a,b) for(int a = 0;a < b;a++)
#define REP(i, x, n) for(int i = x; i < n; i++)
#define P(a) cout << a << endl
#define MP(a,b) make_pair(a,b)
#define PB(a) push_back(a)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
int dx[] = { 1, -1 , 0 , 0 };
int dy[] = { 0,  0,  1, -1 };
ll MOD = 1000000007;
bool compare(pair<int,int> a,pair<int,int> b){
    if(a.first == b.first){
        return a.second < b.second;
    }else{
        return a.first > b.first;
    }
}
void solve() {
    char c[3] = {'A','B','C'};
    vector<pair<int,int>> v;
    map<pair<int,int>,char> m;
    rep(i,3){
        int a,b;
        cin >> a >> b;
        pair<int,int> p = MP(a,b);
        m[p] = c[i];
        v.PB(p);
    }
    sort(v.begin(),v.end(),compare);
    rep(i,3){
        cout << m[v[i]] << endl;
    }
}

int main() {
    solve();
    return 0;
}