// clang-format off
#include <bits/stdc++.h>
#include <iterator>
#include <atcoder/all>
#include <boost/multiprecision/cpp_int.hpp>
#include <boost/multiprecision/integer.hpp>
typedef long long int ll;
#define FOR(i,a,b) for(ll i=(a);i<(b);i++)
#define REP(i,n) for(ll i=0;i<signed(n);i++)
#define EREP(i,n) for(ll i=1;i<=signed(n);i++)
#define ALL(x) std::begin(x), std::end(x)
using namespace std;
using namespace atcoder;
using boost::multiprecision::cpp_int;
namespace mp = boost::multiprecision;
//#define EVEL 1
#ifdef EVEL
#define DEB(X) cout << #X <<":" <<X<<" " ;
#define TF(f) f ? cout<<"true  " : cout<<"false ";
#define END cout<<"\n";
#else
#define DEB(X) {}
#define TF(f) {}
#define END {}
#endif
const ll INF = 9e18;
typedef std::pair<ll, ll> P;
struct edge { ll to, cost; };
#define VMAX 100000
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template <class T> T vgcd(T m, T n) {return std::gcd(m, n);}
template <class T, class... Args> T vgcd(T a, Args... args) {return vgcd(a, vgcd(args...));}
// clang-format on

int dx[]={1,-1,0,0};
int dy[]={0,0,1,-1};


int main(void) {
  ll ans = 0;
  ll N;
  string S;
  cin>>S;
  N=S.size();
  reverse(ALL(S));
  vector<vector<ll>> A(N+1,vector<ll>(26));
  REP(i,N){
    A[i+1][S[i]-'A']++;
  }
  REP(i,N){
    REP(j,26){
      A[i+1][j]+=A[i][j];
    }
  }
  REP(i,N-2){
    REP(j,26){
      if(j+'A'==S[i])continue;
      ans+=(A[N][j] - A[i][j]) * (A[N][j] - A[i][j]-1)/2;
    }
  }
  cout<<ans<<endl;
}