#include <stdio.h>

int main(){
	int height[3] = {0,0,0};
	char str[4] = {'A', 'B', 'C', '\0'};
	
	for(int i = 0;i < 3;i ++){
		scanf("%d",&height[i]);
	}
	// ソート（昇順）
	for(int i = 0;i < 3;i ++){
		for(int j = 0;j < 3;j ++){
			if(height[i] < height[j]){
				int tmp = height[i];
				height[i] = height[j];
				height[j] = tmp;
				int stmp = str[i];
				str[i] = str[j];
				str[j] = stmp;
			}
		}
	}
	for(int i = 0;i < 3;i ++){
		printf("%c\n",str[i]);
	}
}