#include<iostream>
#include<cstdio>
#include<cstring>
#include<queue>
using namespace std;

bool b['z'+1];
int a[100001],ad['z'+1],num,len,que[100001],c[100001];
char s[100001];

int lowbit(int x)
{
	return x&(-x);
}
int sum(int x)
{
	int k=0;
	while(x>0){
		k+=c[x];
		x-=lowbit(x);
	}
	return k;
}
int cut(int x)
{
	while(x<=len)
	{
		c[x]-=1;
		x+=lowbit(x);
	}
}

int main()
{
	freopen("xxxx.in","r",stdin);
	freopen("xxxx.out","w",stdout);
	gets(s);
	len=strlen(s);
	for(int i=0;i<len;i++)
	{
		if(!b[s[i]])
		{
			b[s[i]]=1;
			ad[s[i]]=i+1;
			a[i+1]=1;
		}
		else
		{
			b[s[i]]=0;
			que[i+1]=ad[s[i]];
		}
	}
	for(int i=1;i<=len;i++)
	{
		for(int j=i-lowbit(i)+1;j<=i;j++)  c[i]+=a[j];
	}
	for(int i=1;i<=len;i++)
	{
		if(que[i]!=0)
		{
			num=num+sum(i)-sum(que[i]);
			cut(que[i]);
		}
	}
	printf("%d",num);
	return 0;
}