Problem: 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 >.

The following definition of a regular bracket sequence is well-known, so you can be familiar with it.

Let's define a regular bracket sequence (RBS). Empty string is RBS. Let s1 and s2 be a RBS then the strings <s1>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 RBS.

Input

The only line contains a non empty string s, consisting of only opening and closing brackets of four kinds. The length of s does not exceed 106.

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.

Examples

Input

[&lt;}){}


Output

2

Input

{()}[]


Output

0

Input

]]


Output

Impossible

Solution (in PYTHON3):

Solution:
s = input()
d = ['<', '{', '[', '(']
d2 = ['>', '}', ']', ')']
a = []
k = 0
sum1 = 0
sum2 = 0
for i in s:
    if i in d:
        sum1 += 1
        a.append(d.index(i))
    else:
        sum2 += 1
        if len(a) == 0:
            k = 'Impossible'
            break
        else:
            if a[-1] == d2.index(i):
                a.pop()
            elif a[-1] != d2.index(i):
                a.pop()
                k += 1
if sum1 != sum2:
    print('Impossible')
else:
    print(k)