#include <iostream>
#include <cstdlib>
#include <cmath>
#include <cstdio>
#include <algorithm>


using namespace std;
#define MAXN 27

int niz1[MAXN];
int niz2[MAXN];
char slov[MAXN] ;
int counter = 0 ;
int y = 0 ;


int main ( void ) {
    for ( int i = 0 ; i < 26 ; ++ i ){
    scanf ("%d",& niz1[i]);
    niz2[i]=niz1[i];

    }
    sort (niz1, niz1 + 26 ) ;

    while ( counter < 2 ) {
          y+=1;
          if ( niz2[y] == niz1[24] || niz2[y] == niz1[25]){
             cout<<(char)(y+65);
             counter++;
             }
          else continue;


          }





    //system("PAUSE");
    return 0 ;
    }