ZOJ Problem Set - 3168
Given a string of no more than 1000 characters. You are supposed to sort the characters into a substring of all Z's followed by O's, J's, 7's, and the rest of the other characters.
Each case gives a string described by the problem. The string given contains no space.
For each test case, output the resulting string. Note the order of the characters other than Z, O, J and 7 must be kept after sorting.
Author: CHEN, Yue
Source: ZOJ 7th Anniversary Contest