#include<stdio.h>
int main(){
int a,b,d;
scanf("%d %d",&a,&b);
if(a%b==0)
d=a/b;
else 
d=a/b+1;
int f=31,e=50,p;
if(d<=50)
printf("%02d:%02d",f%24,e-d);
if(50<d&&d<60)
printf("%02d:%02d",(f-1)%24,e+60-d);
if(d>=60)
{if(e-d%60<0)
printf("%02d:%02d",(f-d/60+1)%24,e-d%60+60);
else 
printf("%02d:%02d",(f-d/60)%24,e-d%60);}
return 0;}