#include <stdio.h>

void fr(int n, int a[])
{
  int tmp;

  if (n == 0)
    return;

  tmp = a[0] * a[2] + 1;
  a[2] = a[1];
  a[1] = a[0];
  a[0] = tmp;

  fr(n - 1, a);
}

int f(int n)
{
  int a[3] = { 1, 1, 1 };

  if (n <= 2)
    return 1;

  fr(n - 2, a);

  return a[0];
}

int main(void)
{
  int k;
  for (k = 0; k < 10; k++)
    printf("f(%d) = %d\n", k, f(k));
  return 0;
}