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 (GCC 5.4.1) (judge verdict: Accepted)

#include<stdio.h>
#include<stdlib.h>
#include<string.h>

#define MAX(a,b) ((a)>(b)?(a):(b))
#define MIN(a,b) ((a)<(b)?(a):(b))
#define ABS(a) ((a)>(0)?(a):-(a))

void run(void){
  char *s=(char *)calloc(200000+1,sizeof(char));
  scanf("%s",s);
  int n=strlen(s);
  int *dp=(int *)calloc(1<<26,sizeof(int));
  int i;
  for(i=1;i<(1<<26);i++) dp[i]=n+1;
  dp[0]=0;
  int hash=0;
  for(i=1;i<=n;i++){
    hash^=1<<(s[i-1]-'a');
    int local=dp[hash]+1;
    int j;
    for(j=0;j<26;j++) local=MIN(local,dp[hash^(1<<j)]+1);
    dp[hash]=MIN(local,dp[hash]);
  }
  printf("%d\n",dp[hash]==0?1:dp[hash]);
}

int main(void){
  run();
  return 0;
}