N = int(input())
mod = 10**9+7
dp = [[0]*3 for _ in range(N+1)]
dp[0][0] = 1
for i in range(1, N+1):
    if i == 1:
        dp[i][0] = 1
    elif i == 2:
        dp[i][1] = 1
    else:
        for j in range(3):
            dp[i][j] = dp[i-j-1][(j+1)%3]+dp[i-j-1][(j+2)%3]
            dp[i][j] %= mod
print(sum(dp[-1])%mod)