#include <iostream>
using namespace std;
int main() {
string str;
cin>>str;
int cnt_a=0;
int cnt_b=0;
for(int i=0; str[i]!='0'; i++){
if(str[i] == 'A')
cnt_a++;
else if(str[i] == 'B'){
cnt_b++;
}
}
if(cnt_a>cnt_b)
cout<<"A"<<endl;
else if(cnt_a == cnt_b)
cout<<"E"<<endl;
else if(cnt_a <cnt_b)
cout<<"B"<<endl;
return 0;
}
// 64 位输出请用 printf("%lld")

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