#!/usr/bin/python3
mod = 1000

def matmul(A, B):
    p, q = len(A[0]), len(B)
    if p != q:
        raise ValueError('len(A[0])={} len(B)={}'.format(p, q))
    rows, cols, times = len(A), len(B[0]), len(A[0])
    res = [[0] * cols for _ in range(rows)]
    for r in range(rows):
        for c in range(cols):
            res[r][c] = sum(A[r][i]*B[i][c] for i in range(times)) % mod
    return res

def matpow(A, n):
    m = len(A)
    res = [[int(i==j) for j in range(m)] for i in range(m)]
    while n > 0:
        if n & 1:
            res = matmul(res, A)
        A = matmul(A, A)
        n >>= 1
    return res

n = int(input())
assert 0 <= n <= 10**9
mat = [[1, 3], [1, 1]]
powed = matpow(mat, n)
res = (2*powed[0][0] + ((n&1) - 1)) % mod
print(res)