Make it Happy

Limits: 2 sec., 256 MiB

This statement was translated automatically from Ukrainian.

Today everyone is celebrating Happy Numbers Day!

To celebrate, Marichka and Zenyk came up with a new game. Marichka names a number \(a\), and Zenyk has to find the smallest non-negative number \(b\) such that the sum \(a + b\) consists only of the digits 4 and 7.

Zenyk thought this game was very simple, so he figured he could write a program to find the corresponding \(b\) for him. And he asked you to write this program. Help him with his request.

Input

The single line contains a single integer \(a\) – the number named by Marichka.

Output

In the single line, output a single number – the smallest non-negative number \(b\) such that the sum \(a + b\) consists only of the digits 4 and 7.

Constraints

\(0 \le a \le 10^5\).

Samples