// #pragma GCC target("avx2") // #pragma GCC optimize("O3") // #pragma GCC optimize("unroll-loops") #include using namespace std; using ll = long long; using ull = unsigned long long; template using pq = priority_queue; template using qp = priority_queue, greater>; #define vec(T, A, ...) vector A(__VA_ARGS__); #define vvec(T, A, h, ...) vector> A(h, vector(__VA_ARGS__)); #define vvvec(T, A, h1, h2, ...) vector>> A(h1, vector>(h2, vector(__VA_ARGS__))); #ifndef RIN__LOCAL #define endl "\n" #endif #define spa ' ' #define len(A) A.size() #define all(A) begin(A), end(A) #define fori1(a) for(ll _ = 0; _ < (a); _++) #define fori2(i, a) for(ll i = 0; i < (a); i++) #define fori3(i, a, b) for(ll i = (a); i < (b); i++) #define fori4(i, a, b, c) for(ll i = (a); ((c) > 0 || i > (b)) && ((c) < 0 || i < (b)); i += (c)) #define overload4(a, b, c, d, e, ...) e #define fori(...) overload4(__VA_ARGS__, fori4, fori3, fori2, fori1)(__VA_ARGS__) template vector> ENUMERATE(vector &A, ll s = 0){ vector> ret(A.size()); for(int i = 0; i < A.size(); i++) ret[i] = {i + s, A[i]}; return ret; } vector> ENUMERATE(string &A, ll s = 0){ vector> ret(A.size()); for(int i = 0; i < A.size(); i++) ret[i] = {i + s, A[i]}; return ret; } #define enum1(A) fori(A.size()) #define enum2(a, A) for(auto a:A) #define enum3(i, a, A) for(auto&& [i, a]: ENUMERATE(A)) #define enum4(i, a, A, s) for(auto&& [i, a]: ENUMERATE(A, s)) #define enum(...) overload4(__VA_ARGS__, enum4, enum3, enum2, enum1)(__VA_ARGS__) template vector> ZIP(vector &A, vector &B){ int n = min(A.size(), B.size()); vector> ret(n); for(int i = 0; i < n; i++) ret[i] = {A[i], B[i]}; return ret; } template vector> ENUMZIP(vector &A, vector &B, ll s = 0){ int n = min(A.size(), B.size()); vector> ret(n); for(int i = 0; i < n; i++) ret[i] = {i + s, A[i], B[i]}; return ret; } #define zip4(a, b, A, B) for(auto&& [a, b]: ZIP(A, B)) #define enumzip5(i, a, b, A, B) for(auto&& [i, a, b]: ENUMZIP(A, B)) #define enumzip6(i, a, b, A, B, s) for(auto&& [i, a, b]: ENUMZIP(A, B, s)) #define overload6(a, b, c, d, e, f, g, ...) g #define zip(...) overload6(__VA_ARGS__, enumzip6, enumzip5, zip4, _, _, _)(__VA_ARGS__) vector stoc(string &S){ int n = S.size(); vector ret(n); for(int i = 0; i < n; i++) ret[i] = S[i]; return ret; } #define INT(...) int __VA_ARGS__; inp(__VA_ARGS__); #define LL(...) ll __VA_ARGS__; inp(__VA_ARGS__); #define STRING(...) string __VA_ARGS__; inp(__VA_ARGS__); #define CHAR(...) char __VA_ARGS__; inp(__VA_ARGS__); #define VEC(T, A, n) vector A(n); inp(A); #define VVEC(T, A, n, m) vector> A(n, vector(m)); inp(A); const ll MOD1 = 1000000007; const ll MOD9 = 998244353; template auto min(const T& a){ return *min_element(all(a)); } template auto max(const T& a){ return *max_element(all(a)); } template auto clamp(T &a, const S &l, const S &r) { return (a > r ? r : a < l ? l : a); } template inline bool chmax(T &a, const S &b) { return (a < b ? a = b, 1 : 0); } template inline bool chmin(T &a, const S &b) { return (a > b ? a = b, 1 : 0); } template inline bool chclamp(T &a, const S &l, const S &r) { auto b = clamp(a, l, r); return (a != b ? a = b, 1 : 0); } void FLUSH(){cout << flush;} void print(){cout << endl;} template void print(Head &&head, Tail &&... tail) { cout << head; if (sizeof...(Tail)) cout << spa; print(forward(tail)...); } template void print(vector &A){ int n = A.size(); for(int i = 0; i < n; i++){ cout << A[i]; if(i != n - 1) cout << ' '; } cout << endl; } template void print(vector> &A){ for(auto &row: A) print(row); } template void print(pair &A){ cout << A.first << spa << A.second << endl; } template void print(vector> &A){ for(auto &row: A) print(row); } template void prisep(vector &A, S sep){ int n = A.size(); for(int i = 0; i < n; i++){ cout << A[i]; if(i == n - 1) cout << endl; else cout << sep; } } template void priend(T A, S end){ cout << A << end; } template void priend(T A){ priend(A, spa); } template void inp(T&... a){ (cin >> ... >> a); } template void inp(vector &A){ for(auto &a:A) cin >> a; } template void inp(vector> &A){ for(auto &row:A) inp(row); } template void inp(pair &A){ inp(A.first, A.second); } template void inp(vector> &A){ for(auto &row: A) inp(row.first, row.second); } template T sum(vector &A){ T tot = 0; for(auto a:A) tot += a; return tot; } template pair, map> compression(vector X){ sort(all(X)); X.erase(unique(all(X)), X.end()); map mp; for(int i = 0; i < X.size(); i++) mp[X[i]] = i; return {X, mp}; } vector> read_edges(int n, int m, bool direct=false, int indexed=1){ vector> edges(n, vector()); for(int i = 0; i < m; i++){ INT(u, v); u -= indexed; v -= indexed; edges[u].push_back(v); if(!direct) edges[v].push_back(u); } return edges; } vector> read_tree(int n, int indexed=1){ return read_edges(n, n - 1, false, indexed); } template vector>> read_wedges(int n, int m, bool direct=false, int indexed=1){ vector>> edges(n, vector>()); for(int i = 0; i < m; i++){ INT(u, v); T w; inp(w); u -= indexed; v -= indexed; edges[u].push_back({v, w}); if(!direct) edges[v].push_back({u, w}); } return edges; } template vector>> read_wtree(int n, int indexed=1){ return read_wedges(n, n - 1, false, indexed); } void solve(){ INT(n); STRING(S); vec(ll, dp, n + 1, 0); vec(ll, L, n + 1, 0); vec(ll, R, n + 1, 0); fori(i, n) L[i + 1] = L[i] + ((S[i] == 'C') ? 0 : 1); fori(i, n - 1, -1, -1) R[i] = R[i + 1] + ((S[i] == 'A') ? 0 : 1); fori(i, n) dp[i] = L[i] * R[i]; ll tot = 0; ll a = 0; fori(i, n){ if(S[i] == 'C') tot += a; else a++; dp[i + 1] += tot; } tot = 0; int c = 0; fori(i, n - 1, -1, -1){ if(S[i] == 'A') tot += c; else c++; dp[i] += tot; } print(max(dp)); } int main(){ cin.tie(0)->sync_with_stdio(0); // cout << fixed << setprecision(12); int t; t = 1; // cin >> t; while(t--) solve(); return 0; }