#include<iostream>
#include<cstring>
using namespace std;
char a[100010];
int la,b[100010],h[100010];
long long ans=0;
int main()
{
    freopen("xxxx.in","r",stdin);
    freopen("xxxx.out","w",stdout);
    memset(b,0,sizeof(b));
    cin>>a;
    la=strlen(a);
    for(int i=0;i<la;i++)
    {
        if(b[i]==0)
        {
            for(int j=i+1;j<la;j++)
            {
                if(a[i]==a[j])
                {
                    h[i]=j;
                    h[j]=i;
                    b[i]=1;
                    b[j]=1;
                }
            } 
        }
    }
    memset(b,0,sizeof(b));
    for(int i=0;i<la;i++)
    {
        if(b[i]==0)
        {
           for(int j=i+1;j<h[i];j++)
           {
               if(h[j]>h[i])
               {
                   ans++;
               }
           } 
           b[i]=1;
           b[h[i]]=1;
        }
    }
    cout<<ans;
    return 0;
}