#include<stdio.h>
int main(void)
{
    char s;
    int coutA=0,coutB=0;
    while((s=getchar())!='0')//关键是要看输入符号结束的设定
    {
        if(s=='A')
            coutA++;
        else
            coutB++;
    }
    if(coutA>coutB)
        printf("A");
    else if(coutA<coutB)
        printf("B");
    else
        printf("E");
    return 0;
}