#include <bits/stdc++.h>

using namespace std;
using llong = long long;
using ldbl = long double;
using lpair = pair<llong, llong>;

#define ALL(x) x.begin(), x.end()

constexpr llong mod = 1e9+7;
constexpr llong inf = mod * mod;

int main() {
  string S;
  cin >> S;

  vector<vector<llong>> dp(3, vector<llong>(26));
  for (int i = 0; i < 26; i++) {
    dp[0][i] = 1;
  }

  llong ans = 0;
  for (auto s: S) {
    for (int i = 0; i < 26; i++) {
      if ('A' + i != s) {
        ans += dp[2][i];
      }
    }
    for (int i = 2; i > 0; i--) {
      dp[i][s - 'A'] += dp[i-1][s - 'A'];
    }
  }

  cout << ans << endl;

  return 0;
}