n = int(input())

ken1 = 1
ken2 = 0
pa = 0

for i in range(1, n):
    nextken1 = pa
    nextken2 = ken1
    nextpa = (ken1 + ken2) % 1000000007

    ken1 = nextken1
    ken2 = nextken2
    pa = nextpa

ans = (ken1 + ken2 + pa) % 1000000007
print(ans)