class Fibonacci {

  public static void main(String[] args) {
    /* comment goes here */
    System.out.println(fib(40));
    System.out.println(bfib(40));
  }

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

  static int bfib(int n) {
    int fNMinusTwo = 0;
    int fNMinusOne = 1;

    if (n < 2)
      return n;
    else {
      for (int i = 2; i < n; i++) {
        fNMinusOne = fNMinusOne + fNMinusTwo;
        fNMinusTwo = fNMinusOne - fNMinusTwo;
      }
      return fNMinusOne + fNMinusTwo;
    }
  }

}