#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <utility>
#include <string>
#include <queue>
#include <stack>
#include <unordered_map>

using namespace std;

typedef long long int ll;
typedef pair<int, int> Pii;

const ll mod = 998244353;

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  string s;
  cin >> s;

  int n = s.size();

  ll ans = 0;
  for (char c = 'A'; c <= 'Z'; c++) {
    vector<vector<ll>> dp(n + 1, vector<ll>(4));
    dp[0][0] = 1;
    for (int i = 0; i < n; i++) {
      dp[i + 1][0] = dp[i][0];
      dp[i + 1][1] = dp[i][1] + (s[i] == c ? dp[i][0] : 0);
      dp[i + 1][2] = dp[i][2] + (s[i] == c ? dp[i][1] : 0);
      dp[i + 1][3] = dp[i][3] + (s[i] != c ? dp[i][2] : 0);
    }
    ans += dp[n][3];
  }

  cout << ans << endl;

  return 0;
}