#include #include #include using namespace std; /* #include using namespace atcoder; using mint = modint1000000007; */ #define all(x) (x).begin(),(x).end() #define rep(i, n) for (int i = 0; i < (n); i++) #define endl "\n" #pragma GCC optimize("O3") #pragma GCC optimize("unroll-loops") typedef long long ll; typedef pair pii; typedef pair pll; template ostream &operator<<(ostream &os, const vector &vec) {os << "["; for (const auto &v : vec) {os << v << ","; } os << "]"; return os;} template ostream &operator<<(ostream &os, const pair &p) {os << "(" << p.first << ", " << p.second << ")"; return os;} ll mod_pow(ll a, ll n, ll mod) { ll ret = 1; ll p = a % mod; while (n) { if (n & 1) ret = ret * p % mod; p = p * p % mod; n >>= 1; } return ret; } const int mod = 1e9 + 7; void solve() { string S; cin >> S; vector> acc(S.size() + 1, vector(26)); for (int i = 0; i < S.size(); i++) { for (int j = 0; j < 26; j++) { if (j == S[i] - 'A') { acc[i + 1][j] = acc[i][j] + 1; } else { acc[i + 1][j] = acc[i][j]; } } } ll ans = 0; for (ll i = 0; i < S.size(); i++) { ll j = S[i] - 'A'; ll prevc = acc[i][j]; ll nextc = (S.size() - (i + 1)) - (acc[S.size()][j] - acc[i + 1][j]); ans += prevc * nextc; } cout << ans << endl; } int main() { #ifdef LOCAL_ENV cin.exceptions(ios::failbit); #endif cin.tie(0); ios::sync_with_stdio(false); cout.setf(ios::fixed); cout.precision(16); solve(); }