#include <bits/stdc++.h>
#define REP(i, a, n) for(ll i = ((ll) a); i < ((ll) n); i++)
using namespace std;
typedef long long ll;
typedef pair<ll, char> plc;

int main(void) {
  plc A[3];
  REP(i, 0, 3) {
    cin >> A[i].first;
    A[i].second = 'A' + i;
  }

  sort(A, A + 3);
  reverse(A, A + 3);

  REP(i, 0, 3) cout << A[i].second << endl;
}