def mult(a, b, c, d):
    return (a * c + b * d * 3) % 1000, (a * d + b * c) % 1000

def mypow(n):
    pow2 = (1, 1)
    ans = (1, 0)
    while n:
        if n & 1:
            ans = mult(*ans, *pow2)
        pow2 = mult(*pow2, *pow2)
        n >>= 1
    return ans

def solve(n):
    a, b = mypow(n)
    if n & 1:
        return (a * 2) % 1000
    else:
        return (a * 2 - 1) % 1000

n = int(input())
print(solve(n))