from collections import *
from itertools import *
from functools import *
from heapq import *
import sys,math
input = sys.stdin.readline

N = int(input())
mod = 10**9 + 7


dp = [[0]*(N+1) for _ in range(4)]
dp[1][1] = 1
for i in range(2,N+1):
    
    dp[0][i] = (dp[1][i-1] + dp[2][i-1])%mod
    dp[1][i] = (dp[0][i-1])%mod
    dp[2][i] = dp[1][i-1]%mod

print(sum(dp[j][-1] for j in range(4))%mod)