MOD = int(1e9+7)


def main():
    N = int(input())
    dp_table = [[0, 0, 0, 0] for _ in range(N+1)]
    dp_table[0][0] = 1
    dp_table[0].append(sum(dp_table[0]) % MOD)
    for stair in range(1, N+1):
        for up_stair in range(1, min(stair+1, 4)):
            dp_table[stair][up_stair] = dp_table[stair-up_stair][4] - \
                dp_table[stair-up_stair][up_stair]
        dp_table[stair].append(sum(dp_table[stair]) % MOD)
    print(dp_table[N][4])


if __name__ == "__main__":
    main()