for igor

def uberi(s):
    lol = ""
    for i in range(len(s)-2):
        if i  <= (len(s)-2)//2:
            lol+='1'
        else:
            lol+='0'

    return lol





a = int(input())
ans = ""
s = ""
check = 0
bina = str(bin(a))



for i in range(len(bina) - 2):
    s += bina[2+i]



if(len(s) % 2 == 0):
    kek = len(s) // 2
    tr = len(s) -1
else:
    kek = len(s) // 2 + 1
    tr = len(s)

for i in range(tr):
    if i <= tr // 2:
        ans+='1'
    else:
        ans+='0'




for i in range(kek):
    if a % int(ans,2) == 0 and check == 0:
        check = 1
        print(int(ans,2))

    else:
        if check == 0:
            ans = uberi(ans)