"""
无忧公主的编程挑战004：
斐波那契数列第 12 项 144，是第一个包含 3 个数字的斐波那契数。我的问题是：第一个包含 1000 个数字的斐波那契数，是第几项呢？
"""
def Ghost_Fibonacci(x):
	i = 1
	while True:
		f = Ghost_Fibonacci_Iteration(i)
		if f<10**(x-1):
			i = i + 1
		else:
			break
	print("The first value of Fibonacci sequence which has 1000 figures is NO.%d" % i)	

def Ghost_Fibonacci_Recursion(n):
	if n<=0:
		print("Please enter an positive integer!")
	if n == 1 or n == 2:
		return(1)
	else:
		fn = Ghost_Fibonacci_Recursion(n-1) + Ghost_Fibonacci_Recursion(n-2)
		return(fn)
		
def Ghost_Fibonacci_Iteration(n):
	if n<=0:
		print("Please enter an positive integer!")
	elif n == 1 or n ==2:
		return(1)
	else:
		a,b,c = 1,1,1
		for i in range(n-2):
			c = a + b
			a = b
			b = c
		return(c)
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