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: Memory Limit Exceeded)

#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;
int n,i,j,f[1<<27],ans,c[212345];
string s;
int main()
{
	cin>>s;
	s=" "+s;
	n=s.size();
	for (i=1;i<n;i++)
	{
		c[i]=c[i-1]^(1<<(s[i]-'a'));
	}
	if (!c[n-1]){cout<<"1\n";return 0;}
	memset(f,50,sizeof(f));
	f[0]=0;
	for (i=1;i<n;i++)
	{
		ans=n+n+n+n+345;
		for (j=0;j<26;j++)
		{
			ans=min(ans,f[c[i]^(1<<j)]+1);
		}
		f[c[i]]=min(f[c[i]],ans);
	}
	cout<<f[c[n-1]]<<endl;
	return 0;
}