#include <stdio.h>
int main()
{
	int s, v, m, time, go;
	scanf("%d %d", &s, &v);
	if(s%v==0)
	{
	    m = s / v;
	}
	else if(s%v!=0)
	{
	    m = s / v + 1;
	}
	time = m + 10;
	go = 480 - time;
	if (go % 60 >= 10)
	{
		printf("0%d:%d", go / 60, go % 60);
	}
	else if (go % 60 < 10)
	{
		printf("0%d:0%d", go / 60, go % 60);
	}
	return 0;
}