#include <stdio.h>
int main() {

    char arr[100] = {0};
    int ch = 0;
    int flag = 0;
    while (((ch = getchar()) != '0') && ch != EOF)
       { if (ch == 'A') {
            flag++;

        } else if (ch == 'B') {
            flag--;

        }

}
if (flag > 0)
    printf("A");
else if (flag < 0)
    printf("B");
else
    printf("E");
return 0;
}