We have a string s consisting of lowercase English letters. Snuke is partitioning s into some number of non-empty substrings. Let the subtrings obtained be s_1, s_2, ..., s_N from left to right. (Here, s = s_1 + s_2 + ... + s_N holds.) Snuke wants to satisfy the following condition:

* For each i (1 \leq i \leq N), it is possible to permute the characters in s_i and obtain a palindrome.



Find the minimum possible value of N when the partition satisfies the condition.

Constraints

* 1 \leq |s| \leq 2 \times 10^5
* s consists of lowercase English letters.

Input

Input is given from Standard Input in the following format:


s


Output

Print the minimum possible value of N when the partition satisfies the condition.

Examples

Input

aabxyyzz


Output

2


Input

byebye


Output

1


Input

abcdefghijklmnopqrstuvwxyz


Output

26


Input

abcabcxabcx


Output

3
s = input()
n = len(s)
bits = dict()
bits[0] = 0
bit = 0
for i in range(n):
	x = ord(s[i])-97
	bit ^= (1<<x)
	for j in range(26):
		new_bit = bit ^ (1<<j)
		if new_bit in bits:
			#print(bin(bit)[2:], bin(new_bit)[2:])
			if bit in bits:
				bits[bit] = min(bits[bit], bits[new_bit] + 1)
			else:
				bits[bit] = bits[new_bit] + 1
			#print(bits[bit])
		#print("-----")
if bit not in bits:
	print(-1)
else:
	print(max(1, bits[bit]))