CF893B.Beautiful Divisors

Recently Luba learned about a special kind of numbers that she calls beautiful numbers. The number is called beautiful iff its binary representation consists of $k+1$ consecutive ones, and then $k$ consecutive zeroes.

Some examples of beautiful numbers:

• $1_{2}$ ( $1_{10}$ );
• $110_{2}$ ( $6_{10}$ );
• $1111000_{2}$ ( $120_{10}$ );
• $111110000_{2}$ ( $496_{10}$ ).

More formally, the number is beautiful iff there exists some positive integer $k$ such that the number is equal to $(2^{k}-1)*(2^{k-1})$ .

Luba has got an integer number $n$ , and she wants to find its greatest beautiful divisor. Help her to find it!

The only line of input contains one number $n$ ( $1<=n<=10^{5}$ ) — the number Luba has got.

Output one number — the greatest beautiful divisor of Luba's number. It is obvious that the answer always exists.