def fibonacci(n):
    num1 = 1
    num2 = 1
    tmp = 1

    for i in range(1, n):
        tmp = num1 + num2
        num1 = num2
        num2 = tmp

    return tmp


if __name__ == '__main__':
    n = int(input())
    result = fibonacci(n)
    print(result) def fibonacci(n):
    num1 = 1
    num2 = 1
    tmp = 1

    for i in range(1, n):
        tmp = num1 + num2
        num1 = num2
        num2 = tmp

    return tmp fibonacci num1 = 1 num1 1 num2 = 1 num2 1 tmp = 1 tmp 1 for i in range(1, n):
        tmp = num1 + num2
        num1 = num2
        num2 = tmp

     i range(1, n) range 1 n tmp = num1 + num2 tmp num1 + num2 num1 num2 num1 = num2 num1 num2 num2 = tmp num2 tmp return tmp tmp n n if __name__ == '__main__':
    n = int(input())
    result = fibonacci(n)
    print(result) __name__ == '__main__' __name__ '__main__' n = int(input()) n int(input()) int input() input result = fibonacci(n) result fibonacci(n) fibonacci n print(result) print result result = fibonacci(n) fibonacci(n) result def fibonacci(n):
    num1 = 1
    num2 = 1
    tmp = 1

    for i in range(1, n):
        tmp = num1 + num2
        num1 = num2
        num2 = tmp

    return tmp def fibonacci(n):
    num1 = 1
    num2 = 1
    tmp = 1

    for i in range(1, n):
        tmp = num1 + num2
        num1 = num2
        num2 = tmp

    return tmp fibonacci n = int(input()) int(input()) n
def fibonacci(n):
    num1 = 1
    num2 = 1
    tmp = 1

    for i in range(1, n):
        tmp = num1 + num2
        num1 = num2
        num2 = tmp

    return tmp


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