题解 | #兔子的数量#
兔子的数量
https://www.nowcoder.com/practice/8783056676de4396b0bf816a3561d62f
n = int(input())
n1 = 2
n2 = 3
if n == 1:
print(n1)
elif n == 2:
print(n2)
else:
for j in range(2, n):
nj = n1 + n2
n1 = n2
n2 = nj
print(nj)
