/*
 *  Fibonacci.java by Tue B. Jensen                                    
 *  Print the n'th fibonacci number,
 *  Take the input from the command line.
 *  Measure time elapsed during calculation.
 */

import java.io.*;

class Fibonacci {
    public static long fib(int n) throws Exception {
	if (n < 0) throw(new Exception("Error n<0"));
	switch (n) {
	case 0: return 0;
	case 1: return 1;
	default: return fib(n-1)+fib(n-2);
	}
    }
    
    public static void main(String argv[]) {
	if (argv.length != 1) {
	    System.out.println("Usage ex: java Fibonacci 5");
	    System.exit(1);
	} 
	
	int n = 0;
	try {
	    n =  Integer.parseInt(argv[0]);
	} catch (Exception e) {
	  System.out.println("Error: Integer argument expected.\n"+
			     "Usage ex: java Fibonacci 5");
	  System.exit(2);  
	}
	
	try {	    
	    long start, stop, result;
	    start = System.currentTimeMillis();
	    result = fib(n);
	    stop = System.currentTimeMillis();
	    
	    System.out.println("fib("+n+") Running Time: "+(stop-start)+"ms");
	    System.out.println("fib("+n+") = "+result);
	} catch (Exception e) {
	    System.out.println(e);
	}
    }
}