import java.util.*;

public class Main {
  public static void main(String[] args) {
          Scanner sc = new Scanner(System.in);
          String alpha = sc.next();
          switch(alpha){
            case "a":
              System.out.println("b");
              break;
              case "b":
                System.out.println("c");
                break;
                case "c":
                  System.out.println("d");
                  break;                
                case "d":
                  System.out.println("e");
                  break;
                  case "e":
                    System.out.println("f");
                    break;
                    case "f":
                      System.out.println("g");
                      break;
                      case "g":
                        System.out.println("h");
                        break;                      
                        case "h":
                          System.out.println("i");
                          break;
                          case "i":
                            System.out.println("j");
                            break;
                            case "j":
                              System.out.println("k");
                              break;
                              case "k":
                                System.out.println("l");
                                break;
                                case "l":
                                  System.out.println("m");
                                  break;
                                  case "m":
                                    System.out.println("n");
                                    break;
                                    case "n":
                                      System.out.println("o");
                                      break;   
                                      case "o":
                                        System.out.println("p");
                                        break;
                                        case "p":
                                          System.out.println("q");
                                          break;
                                          case "q":
                                            System.out.println("r");
                                            break;                                                                     
                                            case "r":
                                              System.out.println("s");
                                              break;
                                              case "s":
                                                System.out.println("t");
                                                break;
                                                case "t":
                                                  System.out.println("u");
                                                  break;
                                                  case "u":
                                                    System.out.println("v");
                                                    break;               
                                                    case "v":
                                                      System.out.println("w");
                                                      break;
                                                      case "w":
                                                        System.out.println("x");
                                                        break;
                                                        case "x":
                                                          System.out.println("y");
                                                          break; 
                                                          case "y":
                                                            System.out.println("z");
                                                            break;                                                        
          }
          }
    }


Measured memory_bytes: 21716