Problem:
Score : 700 points

Problem Statement

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.

Sample Input 1

aabxyyzz

Sample Output 1

2

The solution is to partition s as aabxyyzz = aab + xyyzz.
Here, aab can be permuted to form a palindrome aba, and xyyzz can be permuted to form a palindrome zyxyz.

Sample Input 2

byebye

Sample Output 2

1

byebye can be permuted to form a palindrome byeeyb.

Sample Input 3

abcdefghijklmnopqrstuvwxyz

Sample Output 3

26

Sample Input 4

abcabcxabcx

Sample Output 4

3

The solution is to partition s as abcabcxabcx = a + b + cabcxabcx.

Solution in Python (3.4.3) (judge verdict: Time Limit Exceeded)

S = input()
dic = {s : S.count(s) for s in set(S)}
log = {}

def f(S):
    try:
        return log[S]
    
    except KeyError:
        if check(S):
            return 1
        else:
            res = len(S)
            for i in range(1, len(S) - 1):
                res = min(f(S[:i]) + f(S[i:]), res)
                log[S] = res
            return res
    
def check(S):
    flag = False
    for s in set(S):
        if S.count(s) % 2 == 1:
            if flag:
                return False
            else:
                flag = True
    return True

print(f(S))