#include<iostream>
using namespace std;
int main(){
string ch;
int a = 0, b = 0;
getline(cin, ch);
for(int i = 0; ch[i] != '0'; i++){
if(ch[i] == 'A') a++;
else if(ch[i] == 'B') b++;
}
if(a > b) cout << 'A' << endl;
else if(a < b) cout << 'B' << endl;
else cout << 'E' << endl;
return 0;
}
getline(cin, ch)是用标准输入流cin给字符串变量ch里面装入从键盘上输入的字符串