#ifdef SENJAN
#define _GLIBCXX_DEBUG
#else
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#endif
#include <bits/stdc++.h>
#include <atcoder/all>
#include <boost/multiprecision/cpp_int.hpp>
using namespace std;
using namespace atcoder;
using ll=long long;
using ull=unsigned long long;
using ld=long double;
using bint = boost::multiprecision::cpp_int;
using graph=vector<vector<int>>;
template<class T> using min_priority_queue=priority_queue<T,vector<T>,greater<T>>;
constexpr int INF32=INT_MAX/2;
constexpr ll INF64=LLONG_MAX/2;
constexpr ld PI=3.14159265358979323846;
constexpr int dx[]={0,0,-1,1,-1,-1,1,1},dy[]={-1,1,0,0,-1,1,-1,1};
template<class T> inline bool chmax(T &a,T b){return a<b?a=b,true:false;}
template<class T> inline bool chmin(T &a,T b){return a>b?a=b,true:false;}
inline void dispYN(bool a){cout<<(a?"YES":"NO")<<endl;}
inline void dispYn(bool a){cout<<(a?"Yes":"No")<<endl;}
inline void dispyn(bool a){cout<<(a?"yes":"no")<<endl;}
void _main();
int main(){cin.tie(0)->sync_with_stdio(0);cout<<fixed<<setprecision(16);_main();}

void _main(){
  string s; cin >> s;
  int n = s.length();

  vector dp(n+1, vector(26, vector<ll>(3)));
  auto idx = [&](char c){ return c-'A'; };
  ll ans = 0;
  for(int i=0; i<26; i++){
    dp[0][i][0] = 1;
  }
  for(int i=0; i<n; i++){
    for(int j=0; j<26; j++){
      for(int k=0; k<=2; k++){
        dp[i+1][j][k] = dp[i][j][k];
      }
    }
    for(int j=0; j<2; j++){
      dp[i+1][idx(s[i])][j+1] += dp[i][idx(s[i])][j];
    }
    for(int j=0; j<26; j++){
      if(j!=idx(s[i])) ans += dp[i+1][j][2];
    }
  }
  cout << ans << endl;
}