#include <stdio.h>
#include <math.h>

long int n, k, hour;
double x, y;
int main(void)
{
   scanf("%ld%ld", &n, &k);
   if (n == 1)
   {
      printf("0\n");
      return 0;
   }
   n--;
   x = floor(log(k)/log(2)) + 1;
   y = pow(2, x) - 1;
   n -= y;
   hour = x;
   hour += n / k;
   if (n % k != 0)
       hour++;
   printf("%ld\n", hour);
   return 0;
}

What the fucking test.
I test this program on sophisticated tests but
vsio katu pod xvost.
:-P

if you find your mistake, please tall me.

I got WA#3 first, but now - AC.
Try K>N into your program.