N = int(input())
dp = [[0] * 4 for _ in range(N+10)]

P = 10 ** 9 + 7
dp[1][1] = 1
dp[2][2] = 1
dp[3][3] = 1
for i in range(1,N+1):
    for j in range(1,4):
        if i + j <= N:
            for u in range(1,4):
                if u == j:continue
                else:
                    dp[i+j][j] = (dp[i+j][j] + dp[i][u]) % P
ans = dp[N][1] + dp[N][2] + dp[N][3]
print(ans % P)