#!/usr/bin/python
def fib(n):    # write the first n Fibonacci numbers
    a, b = 0, 1
    for i in range(n):
        print i,a
        a, b = b, a+b
        
def fib1(n):   # write Fibonacci series up to n
     """Print a Fibonacci series up to n."""
     a, b = 0, 1
     while a < n:
         print a,
         a, b = b, a+b
         
fib(20)
print ''
fib1(2000)