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

    def count_courses(self, n=None):
        if n is None:
            n = self.number
        m = self.memo[n]
        if m != UNDETERMINED:
            return m
        else:
            result = (self.count_courses(n - 2) +
                      self.count_courses(n - 3)) % self.modulus
            self.memo[n] = result
            return result


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