# coding=gbk
# 迭代法---1

def fibonacci (n):
    if n == 0 or n == 1:
        return n
    else :
        a = 0
        b = 1
        for i in range (n-1) :
            t = a
            a = b
            b = a + t
        return b
number = eval (input ("请输入您要计算的斐波那契数列的项\n"))
cc= fibonacci (number)
print (cc)

# 迭代法---2
def fibonacci2 (n):
    print ("n is "+str(n))
    terms = [0,1]
    i = 2
    while i <= n :
        terms.append(terms[i-1] + terms[i-2])
        i = i + 1
    return terms[n]

number = eval (input ("请输入您要计算的斐波那契数列的项\n"))
cc= fibonacci2 (number)
print (cc)     

# 递归法---1
def fibonacci1 (n):
    print ('n is '+ str(n))
    if n == 0 or n == 1 :
        return n
    else :
        return fibonacci1 (n - 1) + fibonacci1 (n - 2)     

number = eval (input ("请输入您要计算的斐波那契数列的项\n"))
cc= fibonacci1 (number)
print (cc)

# coding=gbk#或者# coding: utf-8