#region Header
#!/usr/bin/env python3
# from typing import *

import sys
import io
import math
import collections
import decimal
import itertools
from queue import PriorityQueue
import bisect
import heapq

def input():
    return sys.stdin.readline()[:-1]

sys.setrecursionlimit(1000000)
#endregion

# _INPUT = """# paste here...
# """
# sys.stdin = io.StringIO(_INPUT)

MOD = 1000000007

def main():
    N = int(input())

    if N == 1:
        return 1
    else:
        dp0 = 0
        dp1 = 1
        dp2 = 0
    for i in range(1, N):
        _dp0 = dp1 + dp2
        _dp1 = dp0
        _dp2 = dp1
        dp0, dp1, dp2 = _dp0, _dp1, _dp2

    print((dp0 + dp1 + dp2) % MOD)

if __name__ == '__main__':
    main()