#include <iostream>
#include <algorithm>
using namespace std;

int main(){
    int a, b, c;
    cin >> a >> b >> c;
  	int k[3] = {a,b,c};
  	sort(k, k+3, greater<int>());
	
    for ( int i = 0; i < 3; i++ ){
		if ( k[i] == a ) cout << "A" << endl;
        if ( k[i] == b ) cout << "B" << endl;
        if ( k[i] == c ) cout << "C" << endl;
    }
    return 0;
}