#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
using namespace std;
using ll = long long ;
using P = pair<int,int> ;
using pll = pair<long long,long long>;
constexpr int INF = 1e9;
constexpr long long LINF = 1e17;
constexpr int MOD = 1000000007;

int main(){
    vector<P> s(3);
    rep(i,3){
        cin >> s[i].first;
        s[i].second = i;
    }
    sort(s.begin(),s.end(),greater<P>());
    rep(i,3) cout << (char)(s[i].second + 'A') << endl;
    return 0;
}