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 C# (Mono 4.6.2.0) (judge verdict: Accepted)

using static System.Math;
using static System.Console;
class Z
{
	const int 無限 = 1000000007;
	static void Main() => WriteLine(F(ReadLine()));
	static int F(string S)
	{
		var N = S.Length;
		var bit = new int[N + 1];
		for (var i = 0; i < N; i++) bit[i + 1] = bit[i] ^ (1 << (S[i] - 'a'));
		var s = 0;
		for (var i = 0; i < 26; i++) if ((bit[N] & (1 << i)) != 0) s++;
		if (s <= 1) return 1;
		var dp = new int[N + 1];
		var tb = new int[1 << 26];
		for (var i = 1; i <= N; i++) dp[i] = 無限;
		for (var i = 1; i < (1 << 26); i++) tb[i] = 無限;
		for (var i = 1; i <= N; i++)
		{
			for (var j = 0; j < 26; j++) dp[i] = Min(dp[i], tb[bit[i] ^ (1 << j)] + 1);
			tb[bit[i]] = Min(tb[bit[i]], dp[i]);
		}
		return dp[N];
	}
}