M = 10**9 + 7
N = int(raw_input())
x = [0, 1, 0]
for i in range(N-1):
    y = [0, 0, 0]
    y[0] = (x[1] + x[2]) % M
    y[1] = x[0]
    y[2] = x[1]
    x = y
print sum(x) % M