N = int(input())
MOD = 10 ** 9 + 7
dp1, dp2, dp3 = ([0] * (N + 3) for _ in range(3))
dp1[1] = dp2[2] = dp3[3] = 1
for i in range(1, N):
    dp1[i + 1] = (dp2[i] + dp3[i]) % MOD
    dp2[i + 2] = (dp1[i] + dp3[i]) % MOD
    dp3[i + 3] = (dp1[i] + dp2[i]) % MOD
print((dp1[N] + dp2[N] + dp3[N]) % MOD)