#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<string.h>
int main()
{
	char s[100]; int i = 0, c = 0, d = 0, n = 0;
	scanf("%s", &s);
	n = strlen(s);
	for (i = 0; i<n; i++)
	{

		if (s[i] == 'A')
			c++;
		if (s[i] == 'B')
			d++;
	}
	if (c>d)
		printf("A");
	else if (c == d)
		printf("E");
	else
		printf("B");
	return 0;
}