Leecode70 climbing stairs

'''  A total of  n  rank ,n >= 0;  You can climb at one time  1  or  2  A stair ;  Ask climb  n  How many kinds of climbing methods are there （ The emphasis is bold , It's about climbing , It doesn't count to go ） '''
#  Violence solution 
def climbStairs(n):
    if n == 0 or n == 1:
        return 1
    return climbStairs(n