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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <cstring>
#include <queue>
#include <cmath>
#include <map>
#include <set>
#include <string>
#define SIZE 200005

using namespace std;
typedef long long int ll;
typedef pair <int,int> P;

map <int,int> mp;
char str[SIZE];
bool use[SIZE];

int main()
{
	scanf("%s",&str);
	int n=strlen(str);
	mp[0]=0;
	for(int i=0;i<n;i++)
	{
		int c=str[i]-'a';
		use[c]=!use[c];
		int S=0;
		for(int j=0;j<26;j++) if(use[j]) S|=1<<j;
		int mn=i+1;
		if(mp.count(S)) mn=min(mn,mp[S]+1);
		for(int j=0;j<26;j++)
		{
			if(mp.count(S^(1<<j)))
			{
				mn=min(mn,mp[S^(1<<j)]+1);
			}
		}
		if(!mp.count(S)) mp[S]=mn;
		else mp[S]=min(mp[S],mn);
		if(i==n-1) printf("%d\n",mn);
	}
	return 0;
}