n = int(raw_input())
k = 1
kk = 0
p = 0
n -= 1
while n > 0:
    t = p
    p = (k + kk) % (10**9 + 7)
    kk = k % (10**9 + 7)
    k = t % (10**9 + 7)
    n -= 1
print (k + kk + p) % (10**9 + 7)