#include using namespace std; using int128 = __int128_t; using int64 = long long; using int32 = int; using uint128 = __uint128_t; using uint64 = unsigned long long; using uint32 = unsigned int; #define ALL(obj) (obj).begin(),(obj).end() template using priority_queue_reverse = priority_queue,greater>; constexpr int64 MOD = 1'000'000'000LL + 7; //' constexpr int64 MOD2 = 998244353; constexpr int64 HIGHINF = 1'000'000'000'000'000'000LL; constexpr int64 LOWINF = 1'000'000'000'000'000LL; //' constexpr long double PI = 3.1415926535897932384626433L; template vector multivector(size_t N,T init){return vector(N,init);} template auto multivector(size_t N,T... t){return vector(N,multivector(t...));} template void corner(bool flg, T hoge) {if (flg) {cout << hoge << endl; exit(0);}} template ostream &operator<<(ostream &o, const map&obj) {o << "{"; for (auto &x : obj) o << " {" << x.first << " : " << x.second << "}" << ","; o << " }"; return o;} template ostream &operator<<(ostream &o, const set&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;} template ostream &operator<<(ostream &o, const multiset&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;} template ostream &operator<<(ostream &o, const vector&obj) {o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;} template ostream &operator<<(ostream &o, const deque&obj) {o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;} template ostream &operator<<(ostream &o, const pair&obj) {o << "{" << obj.first << ", " << obj.second << "}"; return o;} void print(void) {cout << endl;} template void print(Head&& head) {cout << head;print();} template void print(Head&& head, Tail&&... tail) {cout << head << " ";print(forward(tail)...);} template void chmax(T& a, const T b){a=max(a,b);} template void chmin(T& a, const T b){a=min(a,b);} vector split(const string &str, const char delemiter) {vector res;stringstream ss(str);string buffer; while( getline(ss, buffer, delemiter) ) res.push_back(buffer); return res;} inline constexpr int msb(int x) {return x?31-__builtin_clz(x):-1;} inline constexpr int64 ceil_div(const int64 a,const int64 b) {return (a+(b-1))/b;}// return ceil(a/b) void YN(bool flg) {cout << (flg ? "YES" : "NO") << endl;} void Yn(bool flg) {cout << (flg ? "Yes" : "No") << endl;} void yn(bool flg) {cout << (flg ? "yes" : "no") << endl;} set st; void rec(string S) { if(st.count(S)) return; st.insert(S); for(int i=0;i class ModInt { public: long long x; constexpr ModInt():x(0) {} constexpr ModInt(long long y) : x(y>=0?(y%mod): (mod - (-y)%mod)%mod) {} ModInt &operator+=(const ModInt &p) {if((x += p.x) >= mod) x -= mod;return *this;} ModInt &operator+=(const long long y) {ModInt p(y);if((x += p.x) >= mod) x -= mod;return *this;} ModInt &operator+=(const int y) {ModInt p(y);if((x += p.x) >= mod) x -= mod;return *this;} ModInt &operator-=(const ModInt &p) {if((x += mod - p.x) >= mod) x -= mod;return *this;} ModInt &operator-=(const long long y) {ModInt p(y);if((x += mod - p.x) >= mod) x -= mod;return *this;} ModInt &operator-=(const int y) {ModInt p(y);if((x += mod - p.x) >= mod) x -= mod;return *this;} ModInt &operator*=(const ModInt &p) {x = (x * p.x % mod);return *this;} ModInt &operator*=(const long long y) {ModInt p(y);x = (x * p.x % mod);return *this;} ModInt &operator*=(const int y) {ModInt p(y);x = (x * p.x % mod);return *this;} ModInt &operator^=(const ModInt &p) {x = (x ^ p.x) % mod;return *this;} ModInt &operator^=(const long long y) {ModInt p(y);x = (x ^ p.x) % mod;return *this;} ModInt &operator^=(const int y) {ModInt p(y);x = (x ^ p.x) % mod;return *this;} ModInt &operator/=(const ModInt &p) {*this *= p.inv();return *this;} ModInt &operator/=(const long long y) {ModInt p(y);*this *= p.inv();return *this;} ModInt &operator/=(const int y) {ModInt p(y);*this *= p.inv();return *this;} ModInt operator=(const int y) {ModInt p(y);*this = p;return *this;} ModInt operator=(const long long y) {ModInt p(y);*this = p;return *this;} ModInt operator-() const {return ModInt(-x); } ModInt operator++() {x++;if(x>=mod) x-=mod;return *this;} ModInt operator--() {x--;if(x<0) x+=mod;return *this;} ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; } ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; } ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; } ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; } ModInt operator^(const ModInt &p) const { return ModInt(*this) ^= p; } bool operator==(const ModInt &p) const { return x == p.x; } bool operator!=(const ModInt &p) const { return x != p.x; } ModInt inv() const {int a=x,b=mod,u=1,v=0,t;while(b > 0) {t = a / b;swap(a -= t * b, b);swap(u -= t * v, v);} return ModInt(u);} ModInt pow(long long n) const {ModInt ret(1), mul(x);for(;n > 0;mul *= mul,n >>= 1) if(n & 1) ret *= mul;return ret;} friend ostream &operator<<(ostream &os, const ModInt &p) {return os << p.x;} friend istream &operator>>(istream &is, ModInt &a) {long long t;is >> t;a = ModInt(t);return (is);} }; using modint = ModInt; /** * @url * @est */ int main() { cin.tie(0);ios::sync_with_stdio(false); int N; cin >> N; string S; cin >> S; map mp; for(char c:S) mp[c-'A']++; vector f(N+1,1); for(int i=1;i<=N;++i) f[i]=f[i-1]*i; cout << f[N]/f[mp[0]]/f[mp[1]]/f[mp[2]] - N << endl; return 0; }