import java.util.Scanner;

public class Encry {
	public static final String ALPHABET="abcdefghijklmnopqrstuvwxyz";
	public static String encrypt(String plainText,int shiftKey)
	{
	plainText=plainText.toLowerCase();
	String cipherText="";
	for(int i=0;i<plainText.length();i++)
	{
		int charPosition=ALPHABET.indexOf(plainText.charAt(i));
		int keyVal=(shiftKey + charPosition)%26;
		char replaceVal=ALPHABET.charAt(keyVal);
		cipherText +=replaceVal;
	}
	return cipherText;
	}

	public static String decrypt(String cipherText, int shiftKey)
	{
		cipherText=cipherText.toLowerCase();
		String plainText="";
		for(int i=0;i<cipherText.length();i++)
		{
			int charPosition=ALPHABET.indexOf(cipherText.charAt(i));
			int keyVal=(charPosition-shiftKey)%26;
			if(keyVal<0)
			{
				keyVal=ALPHABET.length() + keyVal;
			}
			char replaceVal=ALPHABET.charAt(keyVal);
			plainText+=replaceVal;
		}
		return plainText;
	}


public static void main(String args[])
	{
		Scanner sc=new Scanner(System.in);
		System.out.println("enter the string for encryption");
		String message=" ";
		message=sc.next();
		System.out.println("encrypted messege is:");
		System.out.println(encrypt(message,3));
		System.out.println("decrypted messege is:");
		System.out.println(decrypt(encrypt(message,3),3));
		sc.close();
	}
}