MOD = 10 ** 9 + 7
N = int(input())
dp = [[0, 0, 0] for _ in range(N)]  # dp[i][j]:= i+1個目が j = 0: 1個目のケン、1:2個目のケン、2:パの通り数
dp[0] = [1, 0, 0]
for i in range(1, N):
    dp[i][0] = dp[i - 1][2]
    dp[i][1] = dp[i - 1][0]
    dp[i][2] = (dp[i - 1][0] + dp[i - 1][1]) % MOD
print(sum(dp[-1]) % MOD)