➽ Problem:-

https://www.hackerrank.com/challenges/time-conversion/problem

➽ Solution:-

import java.util.*;

import java.io.*;

import java.text.*;

import java.math.*;

import java.util.regex.*;

public class Solution

{

    public static void main(String args[])

    {

        Scanner in = new Scanner(System.in);

        String str = in.nextLine();

        DateFormat inFormat = new SimpleDateFormat("hh:mm:ssaa");

        DateFormat outFormat = new SimpleDateFormat("HH:mm:ss");

 

        Date date = null;

        try

        {

            date = inFormat.parse(str);

        }

        catch(ParseException c )

        {

            c.printStackTrace();

        }

        if(date != null)

        {

            String myDate = outFormat.format(date);

            System.out.println(myDate);

        }

    }

}