#include <bits/stdc++.h>
using namespace std;

int main()
{
int i;
int a, b, c;

	cin >> a;
	cin >> b;
	cin >> c;
	for( i = 200; i >= 150; i-- )
	{
		if( i == a )		cout << "A" << endl;
		else if( i == b )	cout << "B" << endl;
		else if( i == c )	cout << "C" << endl;
	}
}