import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);

        String s = sc.next();

        String h = s.substring(0,2);
        String m = s.substring(3,5);

        int hh = Integer.parseInt(h);
        int mm = Integer.parseInt(m);

        int mf=0;

        if(mm<=54){
            mm = mm+5;
        }
        else{
            mm = mm+5-60;
            mf = 1;
        }

        if(mf==1){
            hh = hh+1;
            if(hh==24){
                hh =0;
            }
        }

        System.out.println(String.format("%02d:%02d",hh,mm));



	}
}