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