memo = {}


def fib(n):
    """
    :param n: non-negative integer
    :return: n-th fibonacci number
    """
    if n == 0 or n == 1:
        return 1

    try:
        return memo[n]
    except KeyError:
        pass

    res = fib(n-1) + fib(n-2)
    memo[n] = res

    return res


n = int(input())
print(fib(n)) memo = {} memo {} def fib(n):
    """
    :param n: non-negative integer
    :return: n-th fibonacci number
    """
    if n == 0 or n == 1:
        return 1

    try:
        return memo[n]
    except KeyError:
        pass

    res = fib(n-1) + fib(n-2)
    memo[n] = res

    return res fib """
    :param n: non-negative integer
    :return: n-th fibonacci number
    """ if n == 0 or n == 1:
        return 1

     n == 0 or n == 1 n == 0 n 0 n == 1 n 1 return 1 1 try:
        return memo[n]
    except KeyError:
        pass

     except KeyError:
        pass

     return memo[n] memo[n] memo n res = fib(n-1) + fib(n-2) res fib(n-1) + fib(n-2) fib(n-1) fib n-1 n 1 fib(n-2) fib n-2 n 2 memo[n] = res memo[n] memo n res return res res n n n = int(input()) n int(input()) int input() input print(fib(n)) print fib(n) fib n n = int(input()) int(input()) n memo = {} {} memo def fib(n):
    """
    :param n: non-negative integer
    :return: n-th fibonacci number
    """
    if n == 0 or n == 1:
        return 1

    try:
        return memo[n]
    except KeyError:
        pass

    res = fib(n-1) + fib(n-2)
    memo[n] = res

    return res def fib(n):
    """
    :param n: non-negative integer
    :return: n-th fibonacci number
    """
    if n == 0 or n == 1:
        return 1

    try:
        return memo[n]
    except KeyError:
        pass

    res = fib(n-1) + fib(n-2)
    memo[n] = res

    return res fib
memo = {}


def fib(n):
    """
    :param n: non-negative integer
    :return: n-th fibonacci number
    """
    if n == 0 or n == 1:
        return 1

    try:
        return memo[n]
    except KeyError:
        pass

    res = fib(n-1) + fib(n-2)
    memo[n] = res

    return res


n = int(input())
print(fib(n))
