#include<bits/stdc++.h>
using namespace std;
using Int = long long;
//INSERT ABOVE HERE
signed main(){
  vector<Int> h(3);
  for(Int i=0;i<3;i++) cin>>h[i];
  vector<Int> v(3);
  iota(v.begin(),v.end(),0);
  sort(v.begin(),v.end(),[&](Int a,Int b){return h[a]>h[b];});
  for(Int x:v) cout<<char('A'+x)<<endl;
  return 0;
}