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:
import sys
 
def input():    return sys.stdin.readline().strip()
def iinput():   return int(input())
def rinput():   return map(int, sys.stdin.readline().strip().split()) 
def get_list(): return list(map(int, sys.stdin.readline().strip().split())) 
 
n=input()
a=['[','<','{','(',']','>','}',')']
k=0
s=[]
for i in range(len(n)):
	if a.index(n[i])> 3:
		if not s:
			s=1
			break
		if s.pop()!= a.index(n[i]) -4:
			k+=1
	else:
		s+=[a.index(n[i])]

if s:
	print('Impossible')
else:
	print(k)