#include <stdio.h>
#include <string.h>

int main(void){
	char b[65];
	char p[7][33] = {
		"1100000011",
		"10000000100000001000000010000000",
		"1111",
		"1000000110000001",
		"11000000011",
		"100000001100000001",
		"110000011",
	};
	char *bi;

	while(true){
		for(int i=0; i<8; ++i){
			scanf("%s", b+i*8);
		}
		bi = strchr(b, '1');
		for(int i=0; i<7; ++i){
			if(memcmp(bi, p[i], strlen(p[i])) == 0){
				printf("%c\n", 'A' + i);
				break;
			}
		}

		if(scanf("%c", b) == EOF){ break; }
		if(scanf("%c", b) == EOF){ break; }
	}
	return 0;
}