import java.util.*;

public class Main{
  
  public static void main(String[] args){
    
    Scanner sc = new Scanner(System.in);
    String s = sc.next();
    
    String[] notes = {"C","C#","D","D#","E","F","F#","G","G#","A","A#","B"};
    
    for(int i=0;i<11;i++){
      if(s.equals(notes[i])){
        System.out.println(notes[i+1]);
        System.exit(0);
      }
    }
    
    System.out.println("C");
  
  }

}