N = int(input())

dp = [[0] * 3 for i in range(N)]
dp[0][1] = 1
MOD = 10 ** 9 + 7
for i in range(1, N):
    dp[i][0] = (dp[i - 1][1] + dp[i - 1][2]) % MOD
    dp[i][1] = dp[i - 1][0]
    dp[i][2] = dp[i - 1][1]
print(sum(dp[-1]) % MOD)