#include <iostream>
#include <string>

using namespace std;

int main(){
  string msg;
  cin >> msg;
  int mid = msg.size() /2 ;
  string first = msg.substr(0, mid);
  string second = msg.substr(mid, mid);

  int rotation_first = 0;
  int rotation_second = 0;
  for(int i = 0; i < first.size(); i++){
    rotation_first += (first[i] - 'A');
    rotation_second += (second[i] - 'A');
  }
  rotation_first = rotation_first % 26;
  rotation_second = rotation_second % 26;
  
  for(int i = 0; i < first.size(); i++){
    first[i] = first[i] + rotation_first;
    if(first[i] > 'Z')
      first[i] = first[i] - 26;
    second[i] = second[i] + rotation_second;
    if(second[i] > 'Z')
      second[i] = second[i] - 26;
  }
  //  cout << "Decrypted first: " << first << endl;
  //  cout << "Decrypted second: " << second << endl;
  string result;
  for(int i = 0; i < first.size(); i++){
    char c = first[i] + (second[i]-'A');
    if (c > 'Z')
      c = c - 26;
    result = result + c;
  }
  cout << result << endl;
  return 0;
}