"""
输出斐波那契数列的前20个数
1 1 2 3 5 8 13 21 ...
Version: 0.1
Author: 骆昊
Date: 2018-03-02
a = 0
b = 1
for _ in range(20):
(a, b) = (b, a + b)
print(a, end=' ')