#include<bits/stdc++.h>
using namespace std;
int main(){
	int s,v,t,t1,time,h,m;
    scanf("%d %d",&s,&v);
    if(s%v==0) t1=s/v;
    else if(s%v!=0) t1=s/v+1;
    t=t1+10;
    if(t>480) time=1440-(t-480);
    else time=480-t;
    h=time/60;
    m=time-60*h;
    if(m!=0){
	   	if(h>=10) printf("%d:%d",h,m);
		else printf("0%d:%d",h,m);
   	}else{
   		if(h>=10) printf("%d:%02d",h,m);
		else printf("0%d:%02d",h,m);
	}
    return 0;
}