#include <stdio.h>
#include <stdlib.h>

int main()
{
  int s,v,n,h,m,l;
  scanf("%d %d",&s,&v);
  n = (s/v)+10;
  if(n<480)
  {
    if(s/v%60 != 0)
    {
      l = 480-n-1;
    }
    else
    {
      l = 480 -n;
    }
  }
  else
  {
    if(s/v%60 != 0)
    {
      l = 1920-n-1;
    }
    else
    {
      l = 1920 -n;
    }
  }
  h = l/60;
  m = l%60;
  if(h<10&&m<10)
  {
    printf("0%d:0%d",h,m);
  }
  else if(h<10&&m>=10)
  {
    printf("0%d:%d",h,m);
  }
  else if(h>=10&&m<10)
  {
    printf("%d:0%d",h,m);
  }
  else if(h>=10&&m>=10)
  {
    printf("%d:%d",h,m);
  }
  return 0;
}