#include<stdio.h>
int main(){
	int s,v;
	scanf("%d %d",&s,&v);
	int hour,minute;
	hour=(s/v)/60;
	if((s/v)%60==0)
		minute=(s/v)%60;
	else{
		minute=(s/v)%60+1;
	}
	if(hour>=24)
		return 0;
	if(minute>50){
		if(hour<=6){
			printf("0%d:%d",6-hour,110-minute);
		}
		else if((30-hour)<10){
			printf("0%d:%d",30-hour,110-minute);
		}
		else{
			printf("%d:%d",30-hour,110-minute);
		}
	}
	else{
		if(minute<=40){
			if(hour<=7){
				printf("0%d:%d",7-hour,50-minute);
			}
			else if((31-hour)<10){
				printf("0%d:%d",31-hour,50-minute);
			}
			else{
				printf("%d:%d",31-hour,50-minute);
			}
		}
		else{
			if(hour<=7){
				printf("0%d:0%d",7-hour,50-minute);
			}
			else if((31-hour)<10){
				printf("0%d:0%d",31-hour,50-minute);
			}
			else{
				printf("%d:0%d",31-hour,50-minute);
			}
		}
	}
	return 0;
	  }