no error

package com.Olympiad2016;

import java.util.Scanner;
public class t {


    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while (true){
            String commandLine = sc.nextLine();
            if (commandLine.equals("start") || commandLine.equals("START")){
                break;
            }
        }
        int msgCounter = 0;
        StringBuilder decryptMsg = new StringBuilder();

        while (true) {
            String commandLine = sc.nextLine();

            if (commandLine.equals("end")|| commandLine.equals("END")) {
                break;
            }

            if (commandLine.equals("")) {
                continue;
            }
            msgCounter++;

            for (int index = commandLine.length() - 1; index >= 0; index--) {
                char currentSymbol = commandLine.charAt(index);

                boolean isFromAtoMLower = commandLine.charAt(index) >= 'a' && commandLine.charAt(index) <= 'm';
                boolean isFromAtoMUpper = commandLine.charAt(index) >= 'A' && commandLine.charAt(index) <= 'M';
                boolean isFromNtoZLower = commandLine.charAt(index) >= 'n' && commandLine.charAt(index) <= 'z';
                boolean isFromNtoZUpper = commandLine.charAt(index) >= 'N' && commandLine.charAt(index) <= 'Z';
                boolean isDigit = commandLine.charAt(index) >= '0' && commandLine.charAt(index) <= '9';

                if (isFromAtoMUpper || isFromAtoMLower) {
                    decryptMsg.append((char) (commandLine.charAt(index) + 13));
                } else if (isFromNtoZUpper || isFromNtoZLower) {
                    decryptMsg.append((char) (commandLine.charAt(index) - 13));
                } else if (isDigit) {
                    decryptMsg.append(commandLine.charAt(index));
                } else {
                    switch (currentSymbol) {
                        case '+':
                            decryptMsg.append(' ');
                            break;
                        case '%':
                            decryptMsg.append(',');
                            break;
                        case '&':
                            decryptMsg.append('.');
                            break;
                        case '#':
                            decryptMsg.append('?');
                            break;
                        case '$':
                            decryptMsg.append('!');
                            break;
                    }
                }
            }
        }

        if (msgCounter == 0){
            System.out.println("No messages sent.");
        }else {
            System.out.printf("Total number of messages: %d\n",msgCounter);
            System.out.println(decryptMsg.toString());
        }
    }
}