p = 10**9+7
N = input()
dp = [0 for i in xrange(N+2)]
dp[0] = 1
for i in xrange(N-1):
	dp[i+2] += dp[i]; dp[i+2] %= p
	dp[i+3] += dp[i]; dp[i+3] %= p
print sum(dp[-4:N+1]) % p