n = int(input())


def memoize(f):
    memo = [1, 1] + [0] * max(0, n - 1)

    def main(i):
        if memo[i]:
            return memo[i]
        result = memo[i] = f(i)
        return result

    return main


@memoize
def fibonacci(i):
    return fibonacci(i - 1) + fibonacci(i - 2)


print(fibonacci(n)) n = int(input()) n int(input()) int input() input def memoize(f):
    memo = [1, 1] + [0] * max(0, n - 1)

    def main(i):
        if memo[i]:
            return memo[i]
        result = memo[i] = f(i)
        return result

    return main memoize memo = [1, 1] + [0] * max(0, n - 1) memo [1, 1] + [0] * max(0, n - 1) [1, 1] 1 1 [0] * max(0, n - 1) [0] 0 max(0, n - 1) max 0 n - 1 n 1 def main(i):
        if memo[i]:
            return memo[i]
        result = memo[i] = f(i)
        return result

     main if memo[i]:
            return memo[i]
         memo[i] memo i return memo[i] memo[i] memo i result = memo[i] = f(i) result f(i) f i = memo[i] = f(i) memo[i] memo i f(i) return result result i i return main main f f def fibonacci(i):
    return fibonacci(i - 1) + fibonacci(i - 2) fibonacci return fibonacci(i - 1) + fibonacci(i - 2) fibonacci(i - 1) + fibonacci(i - 2) fibonacci(i - 1) fibonacci i - 1 i 1 fibonacci(i - 2) fibonacci i - 2 i 2 i i @memoize fibonacci memoize fibonacci print(fibonacci(n)) print fibonacci(n) fibonacci n def memoize(f):
    memo = [1, 1] + [0] * max(0, n - 1)

    def main(i):
        if memo[i]:
            return memo[i]
        result = memo[i] = f(i)
        return result

    return main def memoize(f):
    memo = [1, 1] + [0] * max(0, n - 1)

    def main(i):
        if memo[i]:
            return memo[i]
        result = memo[i] = f(i)
        return result

    return main memoize n = int(input()) int(input()) n def fibonacci(i):
    return fibonacci(i - 1) + fibonacci(i - 2) def fibonacci(i):
    return fibonacci(i - 1) + fibonacci(i - 2) fibonacci
n = int(input())


def memoize(f):
    memo = [1, 1] + [0] * max(0, n - 1)

    def main(i):
        if memo[i]:
            return memo[i]
        result = memo[i] = f(i)
        return result

    return main


@memoize
def fibonacci(i):
    return fibonacci(i - 1) + fibonacci(i - 2)


print(fibonacci(n))