class Solution:
def numWays(self, n: int) -> int:
x, y = 1, 1
for _ in range(n):
x, y = y, x+y
return x
class Solution:
def numWays(self, n: int) -> int:
x, y = 1, 1
for _ in range(n):
x, y = y, x+y
return x