#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <cmath>
#include <map>
#include <queue>
#include <iomanip>
#define MOD 1000000007
typedef long long ll;
using namespace std;

int main(){
  int a,b,c;
  cin>>a>>b>>c;
  
  int ma=max(a,max(b,c));
  if(ma==a) cout<<"A"<<endl;
  else if(ma==b) cout<<"B"<<endl;
  else cout<<"C"<<endl;

  return 0;
}

