#include<stdio.h>

int main(){
	int s,v,t,xs,fz;
	scanf("%d %d",&s,&v);
	t=s/v+10;
	if(s%v!=0)
		t++;
	xs=t/60;
	fz=t%60;
	if(fz!=0)
		xs++;
	if(8-xs>=0||8-xs<-10)
		printf("0");
	if(8-xs>=0)
		printf("%d",8-xs);
	else
		printf("%d",24+(8-xs));
	printf(":");
	if(fz>50||fz==0)
		printf("0");
	if(fz==0)
		printf("0");
	else 
		printf("%d",60-fz);
	return 0;
}

最后一个测试点死活AC不了