题解 | #统计每个月兔子的总数#
统计每个月兔子的总数
https://www.nowcoder.com/practice/1221ec77125d4370833fd3ad5ba72395
n = int(input())
x = 1
arr = [
x, # 1
0, # 2
0, # 3+
]
# print(arr)
for i in range(n-1):
nt = arr[2] + arr[1]
arr[2] += arr[1]
arr[1] = arr[0]
arr[0] = nt
# print(arr)
print(sum(arr))
