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: Wrong Answer)

                            #include <bits/stdc++.h>
                            #include<iostream>
                            #include<cstdio>
                            #include<vector>
                            #include<queue>
                            #include<map>
                            #include<cstring>
                            #include<string>
                            #include <math.h>
                            #include<algorithm>
                        //    #include <boost/multiprecision/cpp_int.hpp>
                            #include<functional>
                    #define int long long
                            #define inf  1000000007
                            #define pa pair<int,int>
                            #define ll long long
                            #define pal pair<double,pa>
                            #define ppa pair<int,int>
                            #define ppap pair<int,pa>
                            #define ssa pair<string,int>
                            #define  mp make_pair
                            #define  pb push_back
                            #define EPS (1e-10)
                            #define equals(a,b) (fabs((a)-(b))<EPS)
                     
                            using namespace std;
                  
                            class Point{
                            	public:
                            	double x,y;
                            	Point(double x=0,double y=0):x(x),y(y) {}
                            	Point operator + (Point p) {return Point(x+p.x,y+p.y);}
                            	Point operator - (Point p) {return Point(x-p.x,y-p.y);}
                            	Point operator * (double a) {return Point(x*a,y*a);}
                            	Point operator / (double a) {return Point(x/a,y/a);}
                            	double absv() {return sqrt(norm());}
                            	double norm() {return x*x+y*y;}
                            	bool operator < (const Point &p) const{
                            		return x != p.x ? x<p.x: y<p.y;
                            	}
                            	bool operator == (const Point &p) const{
                            		return fabs(x-p.x)<EPS && fabs(y-p.y)<EPS;
                            	}
                            };
                            typedef Point Vector;
                     
                            struct Segment{
                            Point p1,p2;
                            };
                             double dot(Vector a,Vector b){
                            	return a.x*b.x+a.y*b.y;
                            }
                            double cross(Vector a,Vector b){
                            	return a.x*b.y-a.y*b.x;
                            }
                        
bool parareru(Point a,Point b,Point c,Point d){
//	if(abs(cross(a-b,d-c))<EPS)cout<<"dd "<<cross(a-b,d-c)<<endl;
	return abs(cross(a-b,d-c))<EPS;
}
double distance_ls_p(Point a, Point b, Point c) {
  if ( dot(b-a, c-a) < EPS ) return (c-a).absv();
  if ( dot(a-b, c-b) < EPS ) return (c-b).absv();
  return abs(cross(b-a, c-a)) / (b-a).absv();
}
bool is_intersected_ls(Segment a,Segment b) {
	if(a.p1==b.p1||a.p2==b.p1||a.p1==b.p2||a.p2==b.p2) return false;
	if(parareru((a.p2),(a.p1),(a.p1),(b.p2))&&parareru((a.p2),(a.p1),(a.p1),(b.p1))){
//		cout<<"sss"<<endl;
		if(dot(a.p1-b.p1,a.p1-b.p2)<EPS) return true;
		if(dot(a.p2-b.p1,a.p2-b.p2)<EPS) return true;
		if(dot(a.p1-b.p1,a.p2-b.p1)<EPS) return true;
		if(dot(a.p1-b.p2,a.p2-b.p2)<EPS) return true;
		return false;
	}
  else return ( cross(a.p2-a.p1, b.p1-a.p1) * cross(a.p2-a.p1, b.p2-a.p1) < EPS ) && ( cross(b.p2-b.p1, a.p1-b.p1) * cross(b.p2-b.p1, a.p2-b.p1) < EPS );
}
 
double segment_dis(Segment a,Segment b){
	if(is_intersected_ls(a,b))return 0;
	double r=distance_ls_p(a.p1, a.p2, b.p1);
	r=min(r,distance_ls_p(a.p1, a.p2, b.p2));
	r=min(r,distance_ls_p(b.p1, b.p2, a.p2));
	r=min(r,distance_ls_p(b.p1, b.p2, a.p1));
	return r;
}
Point intersection_ls(Segment a, Segment b) {
  Point ba = b.p2-b.p1;
  double d1 = abs(cross(ba, a.p1-b.p1));
  double d2 = abs(cross(ba, a.p2-b.p1));
  double t = d1 / (d1 + d2);
 
  return a.p1 + (a.p2-a.p1) * t;
}
 
                string itos( int i ) {
                ostringstream s ;
                s << i ;
                return s.str() ;
                }
                 
                int gcd(int v,int b){
                	if(v>b) return gcd(b,v);
                	if(v==b) return b;
                	if(b%v==0) return v;
                	return gcd(v,b%v);
                }
 
                double distans(double x1,double y1,double x2,double y2){
                	double rr=(x1-x2)*(x1-x2)+(y1-y2)*(y1-y2);
                	return sqrt(rr);
                	
                }
                /*
int pr[100010];
//int inv[100010];
*/ 
int beki(int wa,int rr,int warukazu){
	if(rr==0) return 1ll;
	if(rr==1) return wa%warukazu;
	if(rr%2==1) return (beki(wa,rr-1,warukazu)*wa)%warukazu;
	int zx=beki(wa,rr/2,warukazu);
	return (zx*zx)%warukazu;
}
  /*
void gya(){
	pr[0]=1;
	for(int i=1;i<100010;i++){
		pr[i]=(pr[i-1]*i)%inf;
	}
	for(int i=0;i<100010;i++) inv[i]=beki(pr[i],inf-2);
	
}
 
*/
 //sort(ve.begin(),ve.end(),greater<int>());
                         //----------------kokomade tenpure------------
//vector<double> ans(100000000),ans2(100000000);
/*
int par[200100],ranks[200100],kosuu[200100];     

void shoki(int n){
	for(int i=0;i<n;i++){
		par[i]=i;
		ranks[i]=0;
		kosuu[i]=1;
	}
}

int root(int x){
	return par[x]==x ? x : par[x]=root(par[x]);
}

bool same(int x,int y){
return root(x)==root(y);
}

void unite(int x,int y){
 x=root(x);
 y=root(y);
	int xx=kosuu[x],yy=kosuu[y];
 if(x==y) return;
	if(ranks[x]<ranks[y]){
		par[x]=y;
		kosuu[y]=yy+xx;
	}
 else {
	par[y]=x;
	if(ranks[x]==ranks[y]) ranks[x]=ranks[x]+1;
 	kosuu[x]=yy+xx;
 }
	return;
}
*/
int l;
map<int,int> ma,ma2;
int tai[200020];
int tai2[200020];
int kazu[30]={0};
vector<int> G[200020];


int saiki(int no){
	if(no==l) return 0;
	int y=inf;
	for(int i=0;i<G[no].size();i++){
		y=min(y,saiki(G[no][i]));
		
	}
	return y+1;
}
string s;
signed main(){
cin>>s;
s="2"+s;
 l=s.length()-1;
	tai[0]=-1;
	ma[-1]=0;
	for(int i=1;i<=l;i++){
		kazu[s[i]-'a']++;
		int y=0ll;
		for(int j=0;j<26;j++){
			y*=2ll;
			y += kazu[j]%2;
	//		cout<<y<<endl;
		}
		tai[i]=y;
		ma[y]=i;
	//	cout<<i<<" "<<y<<endl;
	}
	
	int e=1;
	for(auto it=ma.begin();it!=ma.end();it++){
		
		ma2[it->first]=e;
		tai2[e]=it->first;
	//	cout<<"ma2b"<<e<<" "<<tai2[e]<<endl;
		e++;
	}
	
	
	for(int i=1;i<e;i++){
		int y=tai2[i];
		if(y==-1) y=0;
	//	cout<<i<<"   "<<y<<endl;
		for(int i1=0;i1<27;i1++){
			int yy= y^(1ll<<i1);
			if(i1==26)yy=y;
			if(ma2.find(yy)==ma2.end()) continue;
			if(ma[yy]<=ma[i==1? -1:y])continue;
			G[i].pb(ma2[yy]);
	//		cout<<i<<" "<<yy<<" "<<ma2[yy]<<endl;
		}
	}
	
	l=ma2[tai[l]];
//	cout<<l<<endl;
	cout<<saiki(ma2[-1])<<endl;
	
	return 0;
}