mod = 10 ** 9 + 7

n = int(input())
kkp = [[0, 0, 0] for _ in range(n)]
kkp[0] = [1, 0, 0]
for i in range(1, n):
    kkp[i][0] = kkp[i - 1][2]
    kkp[i][1] = kkp[i - 1][0]
    kkp[i][2] = kkp[i - 1][0] + kkp[i - 1][1]
    kkp[i][2] %= mod

print(sum(kkp[-1]) % mod)