Please Sir, Solve this problem in assembly language using emu 8086 with explanation. It would be better to give a screenshot of output. Please ,Do not use any other languages except assembly. Calculate the minimum number of characters you need to change in the string s, so that it contains at least k different letters, or print that it is impossible.

String s consists only of lowercase Latin letters, and it is allowed to change characters only to lowercase Latin letters too.

Input First line of input contains string s, consisting only of lowercase Latin letters (1|s|1000, |s| denotes the length of s).

Second line of input contains integer k (1k26).

Output Print single line with a minimum number of necessary changes, or the word impossible (without quotes) if it is impossible.

Examples input yandex 6 output 0 input yahoo 5 output 1 input google 7 output impossible