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

unsigned long int E ( unsigned long int m , /* To eat m Idlis */
                      unsigned long int i , /* from Day i */
                      unsigned long int n , /* to Day n */
                      unsigned long int B ) /* with max B Idlis per Day,
                                               B = 0 means no bound */
{
   unsigned long int sum, k;

   if (i == n) { /* Possibilities for the last day */
      if (m == 0) return 0;  /* No Idlis left for the last day */
      if (B == 0) return 1;  /* Eat all the remaining Idlis */
      if (m > B) return 0;   /* Too many Idlis left for the last day */
      return 1;              /* Eat all the remaining Idlis */
   }

   /* Error conditions */
   if (i > n) return 0;      /* No eating beyond Day n */
   if (m+i <= n) return 0;   /* Not enough Idlis left for the remaining days */

   sum = 0;                  /* Initialize accumulating sum */

   if (B == 0) {             /* No bound on the number of Idlis per day */
      /* Eat k Idlis on Day i */
      for (k = 1; k <= m+i-n; ++k)
         sum += E(m-k,i+1,n,0);
   } else {
      /* Eat k Idlis on Day i */
      for (k = 1; (k <= m+i-n) && (k <= B); ++k)
         sum += E(m-k,i+1,n,B);
   }

   return sum;
}

int main ()
{
   unsigned long int m, n, B;

   printf("Number of Idlis (m)    : "); scanf("%lu", &m);
   printf("Number of days (n)     : "); scanf("%lu", &n);

   /*** Part 1 ***/
   printf("Part 1: Number of ways = %lu\n", E(m,1,n,0));

   /*** Part 2 ***/
   printf("Max Idlis per day (B)  : "); scanf("%lu", &B);
   printf("Part 2: Number of ways = %lu\n", E(m,1,n,B));

   exit(0);
}