#include <stdio.h>


void main(void){
	int brotherHeight[3] = {0,0,0};
	int orderList[3] = {1,2,3};

	for(int i = 0 ; i < 3;i++){
		scanf("%d",&brotherHeight[i]);
	}
	for(int i = 0 ; i < 3;i++){
		for(int j = i ; j < 3 ; j++){
			if(brotherHeight[i] < brotherHeight[j]){
				int num = brotherHeight[i];
				brotherHeight[i] = brotherHeight[j];
				brotherHeight[j] = num;
				
				num = orderList[i];
				orderList[i] = orderList[j];
				orderList[j] = num;
			}
		}
	}
	for(int i = 0 ; i < 3;i++){
		if(orderList[i] == 1){
			printf("A\n");
		}else if(orderList[i] == 2){
			printf("B\n");
		}else{
			printf("C\n");
		}
	}
}