题解 | #统计每个月兔子的总数#

import sys

# 输出斐波那契数列"""
def tuzi(n):
    if n < 3:
        return 1
    else:
        return tuzi(n - 1) + tuzi(n - 2)

for line in sys.stdin:
    p = int(line.strip())
    print(tuzi(p))