#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<ll, ll>;
using T = tuple<ll, ll, ll>;
// #include <atcoder/all>
// using namespace atcoder;
// using mint = modint1000000007;
#define rep(i, n) for(ll i = 0; i < n; i++)

int main() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    
    string s; cin >> s;
    vector dp(s.size()+1,vector<vector<ll>>(27,vector<ll>(4,0)));
    ll ans = 0;
    dp[0][0][0] = 1;
    rep(i,s.size()) {
        rep(j,27) {
            rep(k,4) {
                dp[i+1][j][k] += dp[i][j][k];
                if( k == 0 ) {
                    dp[i+1][s[i]-'A'+1][k+1] += dp[i][j][k];
                }
                else if( k == 2 ){
                    if( s[i]-'A'+1 != j ) {
                        dp[i+1][s[i]-'A'+1][k+1] += dp[i][j][k];
                    }
                }
                else if( k == 1 ) {
                    if( s[i]-'A'+1 == j ) {
                        dp[i+1][j][k+1] += dp[i][j][k];
                    }
                }
            }
        }
    }
    rep(i,27) ans += dp[s.size()][i][3];
    cout << ans << endl;
    
    return 0;
}