n = int(input())

dp = [[0]*3]*(n+1)
dp[1][0] = 0
dp[1][1] = 1
dp[1][2] = 0

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