Combination Lock

Scrooge McDuck把他最珍贵的积蓄放在一个带组合锁的保险箱里。每次他想把自己赚来的钱放在那里，他都得打开锁。组合锁由n个旋转磁盘组成，每一个磁盘上可能是数字0到9中的任意一个。Scrooge McDuck必须转动一些磁盘，以便将磁盘上的数字旋转成正确密码。在每一次转动，他可以旋转一个磁盘使磁盘上的数字向前或向后。特别是，在一个动作中，他可以从数字0转到数字9，反之亦然。他需要多少次操作才能打开锁？

Scrooge McDuck keeps his most treasured savings in a home safe with a combination lock. Each time he wants to put there the treasures that he's earned fair and square, he has to open the lock. The combination lock is represented by $ n $ rotating disks with digits from 0 to 9 written on them. Scrooge McDuck has to turn some disks so that the combination of digits on the disks forms a secret combination. In one move, he can rotate one disk one digit forwards or backwards. In particular, in one move he can go from digit 0 to digit 9 and vice versa. What minimum number of actions does he need for that?

The first line contains a single integer $ n $ ( $ 1<=n<=1000 $ ) — the number of disks on the combination lock. The second line contains a string of $ n $ digits — the original state of the disks. The third line contains a string of $ n $ digits — Scrooge McDuck's combination that opens the lock.

Print a single integer — the minimum number of moves Scrooge McDuck needs to open the lock.

5
82195
64723

13

In the sample he needs 13 moves: - 1 disk:  - 2 disk:  - 3 disk:  - 4 disk:  - 5 disk: