text: // this should really be 40 choose 20, but 40! is too large to store in C.
  
  #include <stdio.h>
  
  #define SIZE 20
  
  int main(void) {
      int i;
      unsigned long r=1;
      for(i = 1; i < SIZE; i++)
          r *= (SIZE + i)/i;
      printf("%lu\n",r);
      return 0;
  }
  