#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <vector>
#include <cctype>
#include <iomanip>
#define inf 0x7f7f7f7f
using namespace std;
struct ln
{
	int l;
	int r;
}line[50005],rev[50005];
char ch[100005]={0};
int precursors[30]={0},lns=0;
long long ans=0;
int main()
{
	freopen("xxxx.in","r+",stdin);
	freopen("xxxx.out","w+",stdout);
	scanf("%s",ch+1);
	for(int i=strlen(ch+1);i>=1;i--)
	{
		if(precursors[ch[i]-'a']!=0)
		{
			rev[++lns]=(ln){i,precursors[ch[i]-'a']};
			precursors[ch[i]-'a']=0;
		}
		else precursors[ch[i]-'a']=i;
	}
	for(int i=1;i<=lns;i++) line[i]=rev[lns-i+1];
	for(int i=1;i<=lns;i++)
		for(int j=i+1;line[j].l<line[i].r && j<=lns;j++)
			if(line[j].r>line[i].r) ans++;
	cout<<ans<<endl;
	return 0;
}