#include<stdio.h>
#include<math.h>
int main()
{float s,v;
scanf("%f%f",&s,&v);
int t,H;
t=round(10.5+s/v);
int t1,t2,t3,t4; 
H=7;
if((H-t/60)>=0)
{H=H-t/60;
t=t%60;
t=60-t;
t2=H%10;
t1=H/10;
t3=t/10;
t4=t%10;
printf("%d%d：%d%d",t1,t2,t3,t4); 
 } 
 else
 {H=24+(H-t/60);
 t=t%60;
 t=60-t;
t2=H%10;
t1=H/10;
t3=t/10;
t4=t%10;
printf("%d%d：%d%d",t1,t2,t3,t4); 
 }
 return 0;
}