#include<iostream>
#include<vector>
#include<algorithm>
#include<cstdio>
#include<cstdlib>
#include<string>
#include<sstream>
#include<cmath>
#include<numeric>
#include<map>
#include<stack>
#include<queue>
using namespace std;
int inf = 1000000000;

int main(void) {
  vector< pair<int, char> > a(3);
  cin >> a[0].first >> a[1].first >> a[2].first;
  a[0].second = 'A';
  a[1].second = 'B';
  a[2].second = 'C';
  sort(a.begin(), a.end());
  for(int i=2; i>=0; i--){
    cout << a[i].second << endl;
  }

  return 0;
}

// EOF