import numpy as np

mod = 1000

def powMat(A, n):
    B = np.matrix(np.identity(len(A)))
    while n > 0:
        if n & 1:
            B = np.dot(A, B)
            B %= mod
        A = np.dot(A, A)
        A %= mod
        n /= 2
    return B



n = int(input())

A = np.matrix([ [1, 3],
                [1, 1]])

A = powMat(A, n)

v0 = np.matrix([[1, 0]]).T
v = np.dot(A, v0)

print(int(2 * v[0] - (n % 2 == 0)) % mod)