#include <iostream>
#include <vector>
#include <string>
#include <cstring>
#include <math.h>
#include <cmath>
#include <limits.h>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <functional>
#include <stdio.h>
using namespace std;

long long MOD = 1000000007;

int main() {
    vector< pair<int,char> > P(3);
    string S = "ABC";
    for ( int i = 0; i < 3; i++ ) {
        int h;
        cin >> h;
        P[i].first = h;
        P[i].second = S[i];
    }
    sort( P.begin(),P.end() );
    reverse( P.begin(),P.end() );
    for ( int i = 0; i < 3; i++ ) {
        cout << P[i].second << endl;
    }
    return 0;
}