import java.util.ArrayDeque;
import java.util.Arrays;
import java.util.Scanner;

class Main {

	public static void main(String[] args) {
		new Main().run();
	}
	
	void run() {
		Scanner sc = new Scanner(System.in);
		int h=sc.nextInt();
		int m=sc.nextInt();
		String str=sc.next();
		str=str.substring(3, str.length());
		int add_m=(int)(Double.valueOf(str)*60+1e-6);
		m+=add_m;
		h=(h+m/60-9+24)%24;
		m%=60;
		if(m<0) {
			m+=60;
			h=(h-1+24)%24;
		}
		System.out.println((h<10?"0":"")+h+":"+(m<10?"0":"")+m);
	}

	void tr(Object... objects) {
		System.out.println(Arrays.deepToString(objects));
	}
}