Fibonacci Generator

import time

def fib(n):
    try:

        if n < 2:
            return n
        prev = 1
        fib = 1
        for num in range(2, n):
            prev, fib = fib, fib + prev
            #print str(fib) + ", " #remove the hash at the start of this if you want to print each number after generation


        print "\n\nFibonacci " + str(n) + ": \n\n" + str(fib)



    except KeyboardInterrupt:
        print ""        #just used to catch ctrl+c (terminate) on unix-systems







try:


    howMany = long(raw_input("How many fibonacci numbers would you like generated?\nA Max of 100000 is recommended!\nAnything larger can freeze your system until it is generated\n\nInput your number: "))

    start = time.time()
    fib(howMany)
    elapsed = (time.time() - start)




except ValueError:
    print "\n\nPlease enter a number\n\n"
except KeyboardInterrupt:
    print ""
    #just used to catch ctrl+c (terminate) on unix-systems



print "\n\nTime elapsed: " + str(elapsed) + "s\n\n"



print "\n\nGoodbye\n\n"