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

int fib(int n) 
{
  if(n <= 1) {
    return 1;
  }
  return fib(n - 1) + fib(n - 2);
}

int main(int argc, char *argv[])
{
  printf("%d\n", fib(atoi(argv[1])));
  return 0;
}