// to compile: g++ fib1.cpp
//
// to compute the 50th number in the Fibonacci number sequence
// to run: ./a.out 50  

#include <iostream>
#include <stdlib.h>

using namespace std;

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

int main(int argc, char* argv[])
{
  if (argc == 1) cout << "fib(10) = " << fib(10) << "\n";
  else cout << "fib(" << atoi(argv[1]) << ") = " << fib(atoi(argv[1])) << "\n";
 
  return 0;
}