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()
open_b = ["<","{","[","("]
close_b = [">","}","]",")"]
stack = []
d = {open_b[i]:close_b[i] for i in range(4)}
stack = []
ans = 0
for i in range(len(s)):

	stack.append(s[i])
	if len(stack) >= 2 and stack[-1] in close_b and stack[-2] in open_b:
		if d[stack[-2]] != stack[-1]:
			ans = ans + 1
		stack.pop()
		stack.pop()

if len(stack):
	print("Impossible")
	exit()
print(ans)