#include<iostream>
#include<cstdio>
#include<string>
#include<algorithm>
#include<cstring>
using namespace std;
const int maxlen=100000+100;
struct stack{
	int beg,end;
}s[maxlen];

string str;
int n,top,word[26],cnt,i,p;

bool cmp(stack a,stack b){
	return a.beg <b.beg ;
}
int main(){
	freopen("xxxx.in","r",stdin);
	freopen("xxxx.out","w",stdout);
	memset(word,-1,sizeof(word));
	cin>>str;
	cnt=top=0;
	n=str.length() ;
	for(i=0;i<n;i++){
		
		p=(int)str[i]-97;
		
		if(word[p]!=-1){
			s[top].beg =word[p];
			s[top++].end =i;
			word[p]=-1;
		}
		else word[p]=i;
	}
	sort(s,s+top,cmp);
	for(int i=1,e,b;i<top;i++){
		e=s[i].end;b=s[i].beg ;
		for(int j=i-1;j>=0;j--){
			if(e>s[j].end&&b<s[j].end)cnt++;
		}
	}
	cout<<cnt;
	return 0;
	
	
	
}