N = int(input())
MOD = 10 ** 9 + 7

dp = [[0, 0, 0] for _ in range(N + 1)]
dp[1] = [1, 0, 0]
dp[2] = [0, 1, 0]
dp[3] = [1, 1, 1]

for i in range(4, N + 1):
    dp[i][0] = dp[i - 1][1] + dp[i - 1][2] % MOD
    dp[i][1] = dp[i - 2][0] + dp[i - 2][2] % MOD
    dp[i][2] = dp[i - 3][0] + dp[i - 3][1] % MOD

print(sum(dp[N]) % MOD)