regular-bracket-sequence

You are given string s consists of opening and closing brackets of four kinds <>, {}, [], (). There are two types of brackets: opening and closing. You can replace any bracket by another of the same type. For example, you can replace < by the bracket {, but you can't replace it by ) or >. (Opening brackets can be replaced by opening brackets only and closing brackets can be replaced by closing brackets only). 
Let's define a regular bracket sequence (RBS). Empty string is RBS. Let s1 and s2 be a RBS then the strings s2, {s1}s2, [s1]s2, (s1)s2 are also RBS.

For example the string "[[(){}]<>]" is RBS, but the strings "[)()" and "][()()" are not.
Determine the least number of replaces to make the string s a RBS.

Input
First line contains T (number of test cases).
Next line contains a non empty string s, consisting of only opening and closing brackets of four kinds. The length of s does not exceed 10^6.
Output

If it's impossible to get RBS from s print Impossible.

Otherwise print the least number of replaces needed to get RBS from s.

SAMPLE INPUT
3
[<}){}
{()}[]
]]

SAMPLE OUTPUT
2
0
Impossible

Source: hackerearth | Difficulty: EASY


Solutions: