#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import array

UNDETERMINED = -1
MODULUS = 10 ** 9 + 7
ONE = 1
TWO = 2
THREE = 2


class Kenkenpa(object):

    def __init__(self, max_number, one=ONE, two=TWO, three=THREE, modulus=MODULUS):
        self.modulus = modulus
        self.memo = array.array("q", [UNDETERMINED] * (max(4, max_number + 1)))
        self.memo[1] = one
        self.memo[2] = two
        self.memo[3] = three

    def count_courses(self, n):
        for x in range(4, n + 1):
            self.memo[x] = (self.memo[x - 2] + self.memo[x - 3]) % self.modulus
        return self.memo[n]


if __name__ == "__main__":
    n = int(input())
    k = Kenkenpa(n)
    print(k.count_courses(n))