def K(N):
    if N == 1:
        return 1
    elif (N == 2) or (N == 3):
        return 2
    elif N == 4:
        return 3
    a, b, c = 1, 0, 1
    for i in range(N + 1):
        a, b, c = b, c, a + b
    return c % (10 ** 9 + 7)

def main():
    N = int(input())
    print(K(N))

if __name__ == '__main__':
    main()