mod = 10 ** 9 + 7
n = int(input())
dp = [0] * (n + 1)
dp[0], dp[1], dp[2] = 1, 1, 2
for i in range(3, n + 1):
    dp[i] = (dp[i - 2] + dp[i - 3]) % mod
print(dp[-1])