#include <iostream>
#include <string>

class Tribro{

public:
	int length;
	std::string name;
	char rank = 1;
};



int main() {

	Tribro *a = new Tribro;
	Tribro *b = new Tribro;
	Tribro *c = new Tribro;

	a->name = "A";
	b->name = "B";
	c->name = "C";

	std::cin >> a->length >> b->length >> c->length;

	if (a->length > b->length)	{
		b->rank++;
	}
	else {
		a->rank++;
	}
	if (b->length > c->length){
		c->rank++;
	}
	else {
		b->rank++;
	}
	if (c->length > a->length){
		a->rank++;
	}
	else {
		c->rank++;
	}

	if (a->rank==1) {
		std::cout << a->name << std::endl;
	}
	if (b->rank==1) {
		std::cout << b->name<< std::endl;
	}
	if (c->rank == 1) {
		std::cout << c->name << std::endl;
	}
	if (a->rank == 2) {
		std::cout << a->name << std::endl;
	}
	if (b->rank== 2) {
		std::cout << b->name<< std::endl;
	}
	if (c->rank== 2) {
		std::cout << c->name<< std::endl;
	}
	if (a->rank== 3) {
		std::cout << a->name << std::endl;
	}
	if (b->rank== 3) {
		std::cout << b->name << std::endl;
	}
	if (c->rank== 3) {
		std::cout << c->name << std::endl;
	}
}