#include<bits/stdc++.h>
using namespace std;
const long long MaxN = 1e5 + 5;

string s;

long long nxt[MaxN];
long long first[30], pos[30], last[30];

pair<long long,long long> p[30];

void input()
{
    cin >> s;
}
void solve()
{
    long long n = s.size();

    s = " " + s;

    for(long long c=0; c<26; c++)
    {
        first[c] = n + 1;
        last[c] = 0;
    }

    for(long long i=n; i>=1; i--)
    {
        long long c = s[i] - 'a';

        nxt[i] = first[c];
        first[c] = i;
    }

    for(long long c=0; c<26; c++)
        pos[c] = first[c];

    long long ans = 0;

    for(long long i=1; i<n; i++)
    {
        long long cur = s[i] - 'a';

        last[cur] = i;

        if(pos[cur] == i)
            pos[cur] = nxt[i];

        long long k = min(i,n-i);

        long long cnt = 0;

        for(long long c=0; c<26; c++)
        {
            long long lenl = k + 1;
            long long lenr = k + 1;

            if(last[c] != 0)
            {
                long long len = i - last[c] + 1;

                if(len <= k)
                    lenl = len;
            }

            if(pos[c] <= n)
            {
                long long len = pos[c] - i;

                if(len <= k)
                    lenr = len;
            }

            if(lenl != lenr)
            {
                p[cnt] = {
                    min(lenl,lenr),
                    max(lenl,lenr) - 1
                };

                cnt++;
            }
        }

        sort(p,p+cnt);

        long long cnt2 = 0;

        if(cnt > 0)
        {
            long long l = p[0].first;
            long long r = p[0].second;

            for(long long j=1; j<cnt; j++)
            {
                long long newl = p[j].first;
                long long newr = p[j].second;

                if(newl > r+1)
                {
                    cnt2 += r-l+1;

                    l = newl;
                    r = newr;
                }
                else
                    r = max(r,newr);
            }

            cnt2 += r-l+1;
        }

        ans += k-cnt2;
    }

    cout << ans;
}
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    freopen("file.inp", "r", stdin);
    freopen("file.out", "w", stdout);
    input();
    solve();

    return 0;
}