MOD = 1000

def matpow(A, B, w):
    l = len(A)
    while w:
        if w & 1:
            C = [0] * l
            for i in range(l):
                for j in range(l):
                    C[i] += A[i][j] * B[j]
                    C[i] %= MOD
            B = C
        C = [[0] * l for _ in range(l)]
        for i in range(l):
            for j in range(l):
                for k in range(l):
                    C[i][j] += A[i][k] * A[k][j]
                    C[i][j] %= MOD
        A = C
        w >>= 1
    return B

n = int(input())
A = [[1, 3], [1, 1]]
B = [1, 0]
ans = matpow(A, B, n)[0] * 2
if n % 2 == 0:
    ans -= 1
ans %= MOD
print(ans)