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

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