def fibonacci(n):
    a, b = 1, 1
    for i in range(n-1):
        a, b = b, a+b

    return b

if __name__ == '__main__':
    n = int(input())
    print(fibonacci(n)) def fibonacci(n):
    a, b = 1, 1
    for i in range(n-1):
        a, b = b, a+b

    return b fibonacci a, b = 1, 1 a 1 b 1 for i in range(n-1):
        a, b = b, a+b

     i range(n-1) range n-1 n 1 a, b = b, a+b a b b a+b a b return b b n n if __name__ == '__main__':
    n = int(input())
    print(fibonacci(n)) __name__ == '__main__' __name__ '__main__' n = int(input()) n int(input()) int input() input print(fibonacci(n)) print fibonacci(n) fibonacci n n = int(input()) int(input()) n def fibonacci(n):
    a, b = 1, 1
    for i in range(n-1):
        a, b = b, a+b

    return b def fibonacci(n):
    a, b = 1, 1
    for i in range(n-1):
        a, b = b, a+b

    return b fibonacci
def fibonacci(n):
    a, b = 1, 1
    for i in range(n-1):
        a, b = b, a+b

    return b

if __name__ == '__main__':
    n = int(input())
    print(fibonacci(n))