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 <bits/stdc++.h>
using namespace std;
#define maxn 200010
#define sz (1<<(26))
int a[maxn];            

int val[maxn];

int dp[sz];

int ans[maxn];

int main(){
    string s;
    cin>>s;
    int n= s.size();
    for (int i=0; i<n; i++) a[i+1]= s[i]-'a';
    for (int i=1; i<=n; i++){
        val[i]= val[i-1];
        val[i]^=(1<<a[i]);
    }

    for (int i=0; i<sz; i++) dp[i]= maxn;
    dp[0]=0;
    for (int i=1; i<=n; i++){
        int t= maxn;
        t= min(t, dp[val[i]])+1;
        for (int j=0; j<26; j++){
            t= min(t, dp[val[i]^(1<<j)]+1);
        }
        ans[i]= t;
        dp[val[i]]= min(dp[val[i]], t);
    }    
    cout<<ans[n]<<endl; 

}