n = int(input().strip())
div = 10**9 + 7
if n <= 1:
    print(1)
    raise SystemExit
elif n == 2:
    print(1)
    raise SystemExit

t1 = [1, 1, 0]
t2 = [0, 0, 1]
t3 = [0, 0, 0]

for i in range(3, n + 1):
    t1.append((t2[i - 1] + t3[i - 1]) % div)
    t2.append((t1[i - 2] + t3[i - 2]) % div)
    t3.append((t1[i - 3] + t2[i - 3]) % div)

print((t1[-1] + t2[-1] + t3[-1]) % div)