#include<bits/stdc++.h>
using namespace std;
	string s;
	int ans=0,b[100010];
int main(){
	freopen("xxxx.in","r",stdin);
	freopen("xxxx.out","w",stdout);
	cin>>s;
	for(int i=0;i<s.size()-1;i++)
		for(int j=i+1;j<s.size();j++)
			if(s[i]==s[j]&&s[i]!='0'&&s[j]!='0'){
				b[i]=j;
				b[j]=i;
				s[i]='0';
				s[j]='0';
				break;
			}
	for(int i=0;i<s.size()-1;i++)
		for(int j=i+1;j<s.size();j++)
			if(i<b[i]&&j<b[j])if(j<b[i]&&b[j]>b[i])ans++;
	cout<<ans;
	return 0;	
}