def solve():
    import math
    N = int(input())
    if N < 2:
        print(0)
    elif N%2==0:
        print(N-1)
    else:
        x = 2**int(math.log2(N)) - 1
        if x < N/2:
            print(0)
        else:
            n = x*2-N+1
            y = (N-2 if (N-1)%4 == 0 else N-4) - (x + 2)
            print(n + max(y*2, 0))


if __name__ == "__main__":
    solve()