能被15整除的最大整数

给定一个只包含数字（0..9）的字符串，求使用字符串中的某些字符，构造一个能够被15整除的最大整数，注意，字符串中的每个字符只能适用一次。



输入：程序从标准输入读入数据，每行数据由一串数字组成，长度为1到1000.

输出：针对每一行输入，输出一个结果，每个结果占一行，如果无法构造出能够呗15整除的整数，请输出impossible

-Be the largest integer divisible by 15, given a contains only numbers (0 .. 9), string, requiring use of certain characters in the string, one can construct the largest integer divisible by 15, note that each string characters can only be applied once. Input: program read from standard input data, each row of data from the string of numbers, a length of 1 to 1000. Output: for each line of input, output a result of the row for each result, if you can not divisible by 15 is constructed to chant integer, please output impossible