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: Runtime Error)

#include <bits/stdc++.h>
using namespace std;
const int MOD=1e9+7;
//const int MOD=998244353;
const int INF=1e9;
const long long LINF=1e18;
#define int long long
//template
template <typename T>
void fin(T a){
  cout<<a<<endl;
  exit(0);
}
int dp[100005],dp2[70000000],two[27];

//main
signed main(){
  string s;cin>>s; int N=s.size();
  two[0]=1;for(int i=1;i<26;i++)two[i]=two[i-1]*2;
  for(int i=0;i<N;i++)dp[i+1]=dp[i]^two[s[i]-'a'];//dp[i]^dp[j]のbitがちょうど1つの時、s[i]~s[j-1]が回文に出来る
  for(int i=1;i<70000000;i++)dp2[i]=LINF;//dp2[i]:dp[j]=iを満たすjの中で[0,j)での最小値
  for(int i=0;i<N;i++){
    int res=INF;
    for(int j=0;j<27;j++)res=min(res,dp2[dp[i+1]^two[j]]);
    dp2[dp[i+1]]=min(dp2[dp[i+1]],res+1);
  }
  fin(dp2[dp[N]]);
}