#include <stdio.h>
#include <algorithm>
using namespace std;
using ll = long long;

int main() {
	int H[3], I[3];
	for (int i = 0; i < 3; i++)
		scanf("%d", H + i), I[i] = i;
	sort(I, I + 3, [&](int a, int b) {
		return H[a] > H[b];
	});
	for (int i = 0; i < 3; i++)
		printf("%c\n", 'A' + I[i]);
}