#include<stdio.h>

int main()
{
	int  i, sum=0, flag=0;
	char killer;

	for(i=1; i<=4; i++)
	{
		killer = 64 + i;

		sum = (killer!='A') + (killer=='C') + (killer=='D') + (killer!='D');

		if(sum == 3)
		{
			flag = 1;
			printf("%c is the killer.\n",killer);
			break;
		}
	}

	if(flag == 0)
		printf("Can not find\n");
	
	return 0;
}