问题描述：



设有字符串X，我们称在X的头尾及中间插入任意多个空格后构成的新字符串为X的扩展串，如字符串X为“abcbcd”，则字符串“abcb□cd”，“□a□bcbcd□”和“abcb□cd□”都是X的扩展串，这里“□”代表空格字符。 如果A1是字符串A的扩展串，B1是字符串B的扩展串，A1与B1具有相同的长度，那么我们定义字符串A1与B1的距离为相应位置上的字符的距离总和，而两个非空格字符的距离定义为它们的ASCII码的差的绝对值，而空格字符与其它任意字符之间的距离为已知的定值K，空格字符与空格字符的距离为O。在字符串A、B的所有扩展串中，必定存在两个等长的扩展串A1、B1，使得A1与B1之间的距离达到最小，我们将这一距离定义为字符串A、B的距离。 请你写一个程序，求出字符串A、B的距离。



输入：



有多组数据,每一组数据第一行为字符串A，第二行为字符串B，A、B均由小写字母组成且长度均不超过2000，第三行为一个整数K，1≤K≤100，表示空格与其它字符的距离。



输出：



每组数据一行包含一个整数，表示要求的字符串A、B的距离。-Problem Descr iption :



With a string of X, we call the new string is inserted after any number of spaces in the middle of the head and tail and composed for the X X extension string , such as string X is "abcbcd", the string "abcb □ cd", "□ a □ bcbcd □" and "abcb □ cd □" are X extensions string here "□" on behalf of a space character. If A1 is the extended string string A , B1 B is an extension of substrings , A1 and B1 have the same length , then we define a string from the sum of the distances A1 and B1 on the corresponding character position , and the two from the definition of non- space character is absolute difference of their ASCII codes, and the distance to any other character with a space character between a known K, from the space character and the space character value is O. String A, B in all the extended string , and so there must be two extended string length A1, B1, so that the distance between A1 and B1 to a minimum , this distance will be defined as a string A, the