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: Wrong Answer)

using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Globalization;
using System.Diagnostics;
using static System.Console;
//using System.Numerics;
//using static System.Math;

class Program
{
    static void Main()
    {
        //SetOut(new StreamWriter(OpenStandardOutput()) { AutoFlush = false });
        new Program().solve();
        Out.Flush();
    }
    Scanner cin = new Scanner();
    readonly int[] dd = { 0, 1, 0, -1, 0 }; //→↓←↑
    readonly int mod = 1000000007;


    void solve()
    {
        var S = cin.next;
        int N = S.Length;
        var A = new int[26];
        var G = Enumerable.Range(0, 26).Select(i => new List<int>()).ToArray();
        for (int i = 0; i < N; i++)
        {
            A[S[i] - 'a']++;
            G[S[i] - 'a'].Add(i);
        }
        for (int i = 0; i < 26; i++)
        {
            G[i].Add(N + 1);
        }
        int ans = 0;
        for (int i = 0; i < N; i++)
        {
            var c = S[i] - 'a';
            int E = G[c].Count;
            for (int j = E - 1; j >= 0; j--)
            {
                int v = G[c][j];
                if (j == E - 1) v = N;
                if (G[c][j] == i)
                {
                    ans++;
                    break;
                }
                int sa = 0;
                for (int k = 0; k < 26; k++)
                {
                    int l = upper_bound(G[k], v) - lower_bound(G[k], i);
                    if (l % 2 == 1) sa++;
                }
                if (sa >= 2) continue;
                ans++;
                i = v;
                if (sa == 0) i++;
                break;
            }
        }
        WriteLine(ans);

    }
    int upper_bound(List<int> arr, int val)
    {
        int low = 0, high = arr.Count;
        int mid;

        while (low < high)
        {
            mid = ((high - low) >> 1) + low;
            if (arr[mid] <= val) low = mid + 1;
            else high = mid;
        }
        return low;
    }

    int lower_bound(List<int> arr, int val)
    {
        int low = 0, high = arr.Count;
        int mid;

        while (low < high)
        {
            mid = ((high - low) >> 1) + low;
            if (arr[mid] < val) low = mid + 1;
            else high = mid;
        }
        return low;
    }
}

class Scanner
{
    string[] s; int i;
    char[] cs = new char[] { ' ' };
    public Scanner() { s = new string[0]; i = 0; }
    public string[] scan { get { return ReadLine().Split(); } }
    public int[] scanint { get { return Array.ConvertAll(scan, int.Parse); } }
    public long[] scanlong { get { return Array.ConvertAll(scan, long.Parse); } }
    public double[] scandouble { get { return Array.ConvertAll(scan, double.Parse); } }
    public string next
    {
        get
        {
            if (i < s.Length) return s[i++];
            string st = ReadLine();
            while (st == "") st = ReadLine();
            s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
            i = 0;
            return next;
        }
    }
    public int nextint { get { return int.Parse(next); } }
    public long nextlong { get { return long.Parse(next); } }
    public double nextdouble { get { return double.Parse(next); } }
}