题解 | #统计每个月兔子的总数#

import sys

# def fibonacci(n):
#     if n==1 or n==2:
#         return 1
#     else:
#         return fibonacci(n-1)+fibonacci(n-2)

def fibonacci(n):
    if n==1 or n==2:
        return 1
    else:
        temp=[1, 1]
        for i in range(n-2):
            num=temp[i]+temp[i+1]
            temp.append(num)
        return temp[-1]

for line in sys.stdin:
    n=int(line[:-1])    
    print(fibonacci(n))