#include<iostream>
#include<cstdio>
#include<cstring>>
using namespace std;
char a1[100001]={0};
int a[100001]={0},b[27]={0};
bool a2[100001]={0};
int main(){
	freopen("xxxx.in","r",stdin);
	freopen("xxxx.out","w",stdout);
    cin>>a1;
    int lon;
    lon=strlen(a1);
    for(int i=0;i<lon;i++)
    {
    	a[i+1]=(int)a1[i]-96;
	}
	int kk=0;
	for(int i=1;i<=lon;i++)
	{
		if(b[a[i]]==0)
		{
			a2[i]=1;
			b[a[i]]=i;
		}
		else
		{
			a2[b[a[i]]]=0;
			a2[i]=0;
			for(int j=b[a[i]];j<=i;j++)
			{
				if(a2[j]==1)
				{
					kk+=1;
				}
			}
			b[a[i]]=0;
		}
	}
	cout<<kk;
	return 0;
}