#include <iostream>
using namespace std;
void X(int H,int x,int y)
{
	if (H==max(H,max(x,y))){
		cout<<'A'<<endl;
	}else if (H==min(H,min(x,y))){
		cout<<'C'<<endl;
	}else{
		cout<<'B'<<endl;
	}
}
int main(int argc, char* argv[])
{
	int Ha,Hb,Hc;
	cin>>Ha>>Hb>>Hc;
	X(Ha,Hb,Hc);
	X(Hb,Ha,Hc);
	X(Hc,Ha,Hb);
	return 0;
}