n = int(input())

def mod(n):
	return n % (10**9 + 7)

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] = mod(dp[i][1] + dp[i][2])
	dp[i+1][1] = mod(dp[i][0])
	dp[i+1][2] = mod(dp[i][1])
	
print(mod(dp[n][0] + dp[n][1] + dp[n][2]))