#include<bits/stdc++.h>
using namespace std;
int n;
int a[200005],m1[100];
int lowbit(int x)
{
    	return (x&(-x));
}
int add(int i,int k)
{
    	for(;i<=n;i+=lowbit(i))
		a[i]+=k;
}
int sum(int i)
{
    int ans=0;
    for(i;i>0;i-=lowbit(i))
		ans+=a[i];
	return ans;
}
int main()
{
    freopen("xxxx.in","r",stdin);
    freopen("xxxx.out","w",stdout);
    string s;
    cin>>s;
    n=s.size();
    int ans=0;
    for(int i=1;i<=n;i++)
	{
    	int x=s[i-1]-'a'+1;
    	if(!m1[x])
		{
    		add(i,1);
    		m1[x]=i;
    	}
    	else
		{
    		add(m1[x],-1);
    		ans+=(sum(i)-sum(m1[x]));
    		m1[x]=0;
    	}   
    }
    printf("%d",ans);
}