#line 1 "2794.cpp" // #pragma GCC target("avx2,avx512f,avx512vl,avx512bw,avx512dq,avx512cd,avx512vbmi,avx512vbmi2,avx512vpopcntdq,avx512bitalg,bmi,bmi2,lzcnt,popcnt") // #pragma GCC optimize("Ofast") #line 2 "/home/sigma/comp/library/template.hpp" #include using namespace std; using ll = long long; using uint = unsigned int; using ull = unsigned long long; #define rep(i,n) for(int i=0;i=0;i--) #define per1(i,n) for(int i=int(n);i>0;i--) #define all(c) c.begin(),c.end() #define si(x) int(x.size()) #define pb push_back #define eb emplace_back #define fs first #define sc second template using V = vector; template using VV = vector>; template bool chmax(T& x, U y){ if(x bool chmin(T& x, U y){ if(y void mkuni(V& v){sort(all(v));v.erase(unique(all(v)),v.end());} template int lwb(const V& v, const T& a){return lower_bound(all(v),a) - v.begin();} template V Vec(size_t a) { return V(a); } template auto Vec(size_t a, Ts... ts) { return V(ts...))>(a, Vec(ts...)); } template ostream& operator<<(ostream& o,const pair &p){ return o<<"("< ostream& operator<<(ostream& o,const vector &vc){ o<<"{"; for(const T& v:vc) o< D divFloor(D a, D b){ return a / b - (((a ^ b) < 0 && a % b != 0) ? 1 : 0); } template D divCeil(D a, D b) { return a / b + (((a ^ b) > 0 && a % b != 0) ? 1 : 0); } /* x 0 1 2 3 4 5 6 7 8 9 bsr(x) -1 0 1 1 2 2 2 2 3 3 最上位bit */ int bsr(int x){ return x == 0 ? -1 : 31 ^ __builtin_clz(x); } int bsr(uint x){ return x == 0 ? -1 : 31 ^ __builtin_clz(x); } int bsr(ll x){ return x == 0 ? -1 : 63 ^ __builtin_clzll(x); } int bsr(ull x){ return x == 0 ? -1 : 63 ^ __builtin_clzll(x); } /* x 0 1 2 3 4 5 6 7 8 9 bsl(x) -1 0 1 0 2 0 1 0 3 0 最下位bit */ int bsl(int x){ if(x==0) return -1; return __builtin_ctz(x); } int bsl(uint x){ if(x==0) return -1; return __builtin_ctz(x); } int bsl(ll x){ if(x==0) return -1; return __builtin_ctzll(x); } int bsl(ull x){ if(x==0) return -1; return __builtin_ctzll(x); } template T rnd(T l,T r){ //[l,r) using D = uniform_int_distribution; static random_device rd; static mt19937 gen(rd()); return D(l,r-1)(gen); } template T rnd(T n){ //[0,n) return rnd(T(0),n); } #line 1 "/home/sigma/comp/library/math/poly.cpp" /* 2021/04/14 大幅変更 poly 基本, MultipointEval, Interpolate */ #line 1 "/home/sigma/comp/library/math/mint.cpp" /* 任意mod なら template なくして costexpr の行消して global に unsigned int mod = 1; で cin>>mod してから使う 任意 mod はかなり遅いので、できれば "atcoder/modint" を使う */ template struct ModInt{ using uint = unsigned int; using ll = long long; using ull = unsigned long long; constexpr static uint mod = mod_; uint v; ModInt():v(0){} ModInt(ll _v):v(normS(_v%mod+mod)){} explicit operator bool() const {return v!=0;} static uint normS(const uint &x){return (x [0 , mod-1] static ModInt make(const uint &x){ModInt m; m.v=x; return m;} ModInt operator+(const ModInt& b) const { return make(normS(v+b.v));} ModInt operator-(const ModInt& b) const { return make(normS(v+mod-b.v));} ModInt operator-() const { return make(normS(mod-v)); } ModInt operator*(const ModInt& b) const { return make((ull)v*b.v%mod);} ModInt operator/(const ModInt& b) const { return *this*b.inv();} ModInt& operator+=(const ModInt& b){ return *this=*this+b;} ModInt& operator-=(const ModInt& b){ return *this=*this-b;} ModInt& operator*=(const ModInt& b){ return *this=*this*b;} ModInt& operator/=(const ModInt& b){ return *this=*this/b;} ModInt& operator++(int){ return *this=*this+1;} ModInt& operator--(int){ return *this=*this-1;} template friend ModInt operator+(T a, const ModInt& b){ return (ModInt(a) += b);} template friend ModInt operator-(T a, const ModInt& b){ return (ModInt(a) -= b);} template friend ModInt operator*(T a, const ModInt& b){ return (ModInt(a) *= b);} template friend ModInt operator/(T a, const ModInt& b){ return (ModInt(a) /= b);} ModInt pow(ll p) const { if(p<0) return inv().pow(-p); ModInt a = 1; ModInt x = *this; while(p){ if(p&1) a *= x; x *= x; p >>= 1; } return a; } ModInt inv() const { // should be prime return pow(mod-2); } // ll extgcd(ll a,ll b,ll &x,ll &y) const{ // ll p[]={a,1,0},q[]={b,0,1}; // while(*q){ // ll t=*p/ *q; // rep(i,3) swap(p[i]-=t*q[i],q[i]); // } // if(p[0]<0) rep(i,3) p[i]=-p[i]; // x=p[1],y=p[2]; // return p[0]; // } // ModInt inv() const { // ll x,y; // extgcd(v,mod,x,y); // return make(normS(x+mod)); // } bool operator==(const ModInt& b) const { return v==b.v;} bool operator!=(const ModInt& b) const { return v!=b.v;} bool operator<(const ModInt& b) const { return v>(istream &o,ModInt& x){ ll tmp; o>>tmp; x=ModInt(tmp); return o; } friend ostream& operator<<(ostream &o,const ModInt& x){ return o<; //using mint = ModInt<1000000007>; V fact,ifact,invs; // a,b >= 0 のみ mint Choose(int a,int b){ if(b<0 || a= 0 の範囲で、 Choose(a,b) = a(a-1)..(a-b+1) / b! mint Choose(int a,int b){ if(b<0 || a=0;i--) ifact[i] = ifact[i+1] * (i+1); rep1(i,N-1) invs[i] = fact[i-1] * ifact[i]; } #line 7 "/home/sigma/comp/library/math/poly.cpp" // inplace_fmt (without bit rearranging) // fft: // a[rev(i)] <- \sum_j \zeta^{ij} a[j] // invfft: // a[i] <- (1/n) \sum_j \zeta^{-ij} a[rev(j)] // These two are inversions. // !!! CHANGE IF MOD is unusual !!! const int ORDER_2_MOD_MINUS_1 = 23; // ord_2 (mod-1) const mint PRIMITIVE_ROOT = 3; // primitive root of (Z/pZ)* void fft(V& a){ static constexpr uint mod = mint::mod; static constexpr uint mod2 = mod + mod; static const int H = ORDER_2_MOD_MINUS_1; static const mint root = PRIMITIVE_ROOT; static mint magic[H-1]; int n = si(a); assert(!(n & (n-1))); assert(n >= 1); assert(n <= 1<>(i+2))*3); magic[i] = w; } } int m = n; if(m >>= 1){ rep(i,m){ uint v = a[i+m].v; // < M a[i+m].v = a[i].v + mod - v; // < 2M a[i].v += v; // < 2M } } if(m >>= 1){ mint p = 1; for(int h=0,s=0; s>= 1){ mint p = 1; for(int h=0,s=0; s>= 1){ mint p = 1; for(int h=0,s=0; s= mod2) ? a[i].v - mod2 : a[i].v; // < 2M a[i+m].v = a[i].v + mod - v; // < 3M a[i].v += v; // < 3M } p *= magic[__builtin_ctz(++h)]; } } } rep(i,n){ a[i].v = (a[i].v >= mod2) ? a[i].v - mod2 : a[i].v; // < 2M a[i].v = (a[i].v >= mod) ? a[i].v - mod : a[i].v; // < M } // finally < mod !! } void invfft(V& a){ static constexpr uint mod = mint::mod; static constexpr uint mod2 = mod + mod; static const int H = ORDER_2_MOD_MINUS_1; static const mint root = PRIMITIVE_ROOT; static mint magic[H-1]; int n = si(a); assert(!(n & (n-1))); assert(n >= 1); assert(n <= 1<>(i+2))*3); magic[i] = w.inv(); } } int m = 1; if(m < n>>1){ mint p = 1; for(int h=0,s=0; s>1; m <<= 1){ mint p = 1; for(int h=0,s=0; s>1);i++){ ull x = a[i].v + mod2 - a[i+m].v; // < 4M a[i].v += a[i+m].v; // < 4M a[i].v = (a[i].v >= mod2) ? a[i].v - mod2 : a[i].v; // < 2M a[i+m].v = (p.v * x) % mod; // < M } for(int i=s+(m>>1); i 70ms // verify https://judge.yosupo.jp/submission/44937 V multiply(V a, V b) { int A = si(a), B = si(b); if (!A || !B) return {}; int n = A+B-1; int s = 1; while(s 2 a.resize(s); fft(a); rep(i,s) a[i] *= a[i]; }else{ a.resize(s); fft(a); b.resize(s); fft(b); rep(i,s) a[i] *= b[i]; } invfft(a); a.resize(n); return a; } /* 係数アクセス f[i] でいいが、 配列外参照する可能性があるなら at/set */ template struct Poly: public V{ using vector::vector; Poly() {} explicit Poly(int n) : V(n){} // poly a; a = 2; shouldn't be [0,0] Poly(int n, mint c) : V(n,c){} Poly(const V& a) : V(a){} Poly(initializer_list li) : V(li){} int size() const { return V::size(); } mint at(int i) const { return i=size() && !x) return; while(i>=size()) this->pb(0); (*this)[i] = x; return; } mint operator()(mint x) const { // eval mint res = 0; int n = size(); mint a = 1; rep(i,n){ res += a * (*this)[i]; a *= x; } return res; } Poly low(int n) const { // ignore x^n (take first n), but not empty return Poly(this->begin(), this->begin()+min(max(n,1),size())); } Poly rev() const { return Poly(this->rbegin(), this->rend()); } friend ostream& operator<<(ostream &o,const Poly& f){ o << "["; rep(i,f.size()){ o << f[i]; if(i != f.size()-1) o << ","; } o << "]"; return o; } Poly operator-() const { Poly res = *this; for(auto& v: res) v = -v; return res; } Poly& operator+=(const mint& c){ if(this->empty()) this->eb(0); (*this)[0] += c; return *this; } Poly& operator-=(const mint& c){ if(this->empty()) this->eb(0); (*this)[0] -= c; return *this; } Poly& operator*=(const mint& c){ for(auto& v: *this) v *= c; return *this; } Poly& operator/=(const mint& c){ return *this *= mint(1)/mint(c); } Poly& operator+=(const Poly& r){ if(size() < r.size()) this->resize(r.size(),0); rep(i,r.size()) (*this)[i] += r[i]; return *this; } Poly& operator-=(const Poly& r){ if(size() < r.size()) this->resize(r.size(),0); rep(i,r.size()) (*this)[i] -= r[i]; return *this; } Poly& operator*=(const Poly& r){ return *this = multiply(*this,r); } // 何回も同じrで割り算するなら毎回rinvを計算するのは無駄なので、呼び出し側で一回計算した後直接こっちを呼ぶと良い // 取るべきinvの長さに注意 // 例えば mod r で色々計算したい時は、基本的に deg(r) * 2 長さの多項式を r で割ることになる // とはいえいったん rinv を長く計算したらより短い場合はprefix見るだけだし、 rinv としてムダに長いものを渡しても問題ないので // 割られる多項式として最大の次数を取ればよい Poly quotient(const Poly& r, const Poly& rinv){ int m = r.size(); assert(r[m-1].v); int n = size(); int s = n-m+1; if(s <= 0) return {0}; return (rev().low(s)*rinv.low(s)).low(s).rev(); } Poly& operator/=(const Poly& r){ return *this = quotient(r,r.rev().inv(max(size()-r.size(),0)+1)); } Poly& operator%=(const Poly& r){ *this -= *this/r * r; return *this = low(r.size()-1); } Poly operator+(const mint& c) const {return Poly(*this) += c; } Poly operator-(const mint& c) const {return Poly(*this) -= c; } Poly operator*(const mint& c) const {return Poly(*this) *= c; } Poly operator/(const mint& c) const {return Poly(*this) /= c; } Poly operator+(const Poly& r) const {return Poly(*this) += r; } Poly operator-(const Poly& r) const {return Poly(*this) -= r; } Poly operator*(const Poly& r) const {return Poly(*this) *= r; } Poly operator/(const Poly& r) const {return Poly(*this) /= r; } Poly operator%(const Poly& r) const {return Poly(*this) %= r; } Poly diff() const { Poly g(max(size()-1,0)); rep(i,g.size()) g[i] = (*this)[i+1] * (i+1); return g; } Poly intg() const { assert(si(invs) > size()); Poly g(size()+1); rep(i,size()) g[i+1] = (*this)[i] * invs[i+1]; return g; } Poly square() const { return multiply(*this,*this); } // 1/f(x) mod x^s // N = s = 500000 -> 90ms // inv は 5 回 fft(2n) を呼んでいるので、multiply が 3 回 fft(2n) を呼ぶのと比べると // だいたい multiply の 5/3 倍の時間がかかる // 導出: Newton // fg = 1 mod x^m // (fg-1)^2 = 0 mod x^2m // f(2g-fg^2) = 1 mod x^2m // verify: https://judge.yosupo.jp/submission/44938 Poly inv(int s) const { Poly r(s); r[0] = mint(1)/at(0); for(int n=1;n f = low(2*n); f.resize(2*n); fft(f); V g = r.low(2*n); g.resize(2*n); fft(g); rep(i,2*n) f[i] *= g[i]; invfft(f); rep(i,n) f[i] = 0; fft(f); rep(i,2*n) f[i] *= g[i]; invfft(f); for(int i=n;i0)); // 頑張ればできる if(p>0 and (s-1)/p < ord) return Poly(s); // s <= p * ord int off = p*ord; int s_ = s-off; const mint a0 = at(ord), ia0 = a0.inv(), ap = a0.pow(p); Poly f(s_); rep(i,s_) f[i] = at(i+ord) * ia0; f = (f.log(s_) * p).exp(s_); Poly res(s); rep(i,s_) res[i+off] = f[i] * ap; return res; } // f^(1/2) mod x^s // f[0] should be 1 // 11/6 // verify: https://judge.yosupo.jp/submission/44997 Poly sqrt(int s) const { assert(at(0) == 1); static const mint i2 = mint(2).inv(); V f{1},g{1},z{1}; for(int n=1;n d(2*n); rep(i,n) d[n+i] = z[i] - at(i) - at(n+i); fft(d); V g2(2*n); rep(i,n) g2[i] = g[i]; fft(g2); rep(i,n*2) d[i] *= g2[i]; invfft(d); f.resize(n*2); for(int i=n;i= s) break; z = f; fft(z); V eps = g2; rep(i,n*2) eps[i] *= z[i]; invfft(eps); rep(i,n) eps[i] = 0; fft(eps); rep(i,n*2) eps[i] *= g2[i]; invfft(eps); g.resize(n*2); for(int i=n;i= n); // please InitFact V f(n); rep(i,n) f[i] = (*this)[i] * fact[i]; V g(n); mint cpow = 1; rep(i,n){g[i] = cpow * ifact[i]; cpow *= c;} reverse(all(g)); V h = multiply(f,g); Poly res(n); rep(i,n) res[i] = h[n-1+i] * ifact[i]; return res; } // 合成逆 mod x^s // O(s^2 + s^1.5 log s) // 方針: lagrange [x^i]g = (1/i [x^i-1](x/f)^i) // (x/f)^i = (x/f)^jL (x/f)^k とすれば前計算はs^1.5回FFT // 2つの積の一箇所求めるだけなのでO(s) // z をかけまくったり z^L をかけまくったりするところはFFT消せるから高速化できる // verify: https://www.luogu.com.cn/problem/P5809 Poly compositeInv(int s){ assert(at(0) == 0); assert(at(1) != 0); int L = 0; while(L*L < s) L++; Poly z0(s); rep(i,s) z0[i] = at(i+1); Poly z = z0.inv(s); // = x/f V zi(L); // z^i V ziL(L); // z^iL zi[0] = {1}; rep(i,L-1) zi[i+1] = (zi[i] * z).low(s); auto zL = (zi[L-1] * z).low(s); ziL[0] = {1}; rep(i,L-1) ziL[i+1] = (ziL[i] * zL).low(s); Poly res(s); rep1(k,s-1){ int i = k/L, j = k%L; // x^(iL+j) rep(_,k) res[k] += ziL[i].at(_) * zi[j].at(k-1-_); res[k] /= k; } return res; } }; // 合成 f○g mod x^s // O(ns + sqrt(n)slogs) // sを指定しないときはnm次全部返す O(n^2m)? // \sum_k f_k g^k = \sum_k f_k g^iL+j = \sum_i g^iL * (\sum_j f_k g^j) // verify: https://www.luogu.com.cn/problem/P5373 Poly composite(Poly f, Poly g, int s=-1){ int n = si(f)-1, m = si(g)-1; if(s == -1) s = n*m+1; int L = 0; while(L*L <= n) L++; V> gi(L); // g^i V> giL(L); // g^iL gi[0] = {1}; rep(i,L-1) gi[i+1] = (gi[i] * g).low(s); auto gL = (gi[L-1] * g).low(s); giL[0] = {1}; rep(i,L-1) giL[i+1] = (giL[i] * gL).low(s); Poly res(s); rep(i,L){ Poly z; rep(j,L) if(i*L+j <= n) z += gi[j] * f[i*L+j]; res += (z * giL[i]).low(s); } return res; } ll norm_mod(ll a, ll m){ a %= m; if(a < 0) a += m; return a; } //p: odd (not necessarily prime) ll jacobi(ll a,ll p){ a = norm_mod(a,p); auto sgn = [](ll x){ return x&1 ? -1 : 1; }; if(a == 0) return p == 1; else if(a&1) return sgn(((p-1)&(a-1))>>1) * jacobi(p%a,a); else return sgn(((p&15)*(p&15)-1)/8) * jacobi(a/2,p); } // p : prime // 0 <= a < p // return smaller solution // if no solution, -1 ll sqrt_mod(ll a,ll p){ if(a == 0) return 0; if(p == 2) return 1; if(jacobi(a,p) == -1)return -1; ll b,c; for(b=0;;b++){ c = norm_mod(b*b-a,p); if(jacobi(c,p) == -1) break; } auto mul = [&](pair x, pair y){ return pair(norm_mod(x.fs*y.fs+x.sc*y.sc%p*c,p),norm_mod(x.fs*y.sc+x.sc*y.fs,p)); }; pair x(b,1),res(1,0); ll n = (p+1)/2; while(n){ if(n&1) res = mul(res,x); x = mul(x,x); n >>= 1; } assert(res.sc == 0); return min(res.fs, p-res.fs); } // 辞書順最小 // no solution -> {} Poly sqrt(Poly f){ int n = f.size(); int ord = 0; while(ord(f.begin()+ord,f.end())/f[ord]).sqrt(n_) * mint(c0); Poly res(ord/2 + n_); rep(i,n_) res[ord/2 + i] = g[i]; return res; } // Q log^2 Q ではある // 高速なのはうまく subproduct tree を構築するらしい // maroon https://judge.yosupo.jp/submission/3240 160ms // verify: https://judge.yosupo.jp/submission/45006 950ms template V MultipointEval(const Poly& f, V a){ int Q = a.size(); int s = 1; while(s < Q) s *= 2; V> g(s+s,{1}); rep(i,Q) g[s+i] = {-a[i],1}; for(int i=s-1;i>0;i--) g[i] = g[i*2] * g[i*2+1]; g[1] = f % g[1]; for(int i=2;i>1] % g[i]; V res(Q); rep(i,Q) res[i] = g[s+i][0]; return res; } // N log^2 N ではある // 高速なのはうまく subうんぬん template Poly interpolate(const V& x, const V& y){ int n = si(x); int s = 1; while(s> g(s+s,{1}), h(s+s); rep(i,n) g[s+i] = {-x[i],1}; for(int i=s-1;i>0;i--) g[i] = g[i*2] * g[i*2+1]; h[1] = g[1].diff(); for(int i=2;i>1] % g[i]; rep(i,n) h[s+i] = {y[i] / h[s+i][0]}; for(int i=s-1;i>0;i--) h[i] = h[i*2]*g[i*2+1] + h[i*2+1]*g[i*2]; return h[1]; } // [x^p] f/g // O(n logn logp) // O(f logf + g logg logn) (f が大きくてもややOK) // verified: https://ac.nowcoder.com/acm/contest/11259/H // hos,divAt : https://ac.nowcoder.com/acm/contest/view-submission?submissionId=48462458 template T divAt(Poly f, Poly g, ll p){ assert(g.at(0)); while(p){ auto gm = g; for(int i=1;i T linearRecurrenceAt(V a, V c, ll k){ assert(!c.empty() && c[0]); int d = si(c) - 1; assert(si(a) >= d); return divAt((Poly(a.begin(),a.begin()+d) * Poly(c)).low(d), Poly(c), k); } // return f(K+1) // f[k] = 0^k + .. + n^k // \sum_{k>=0} f[k] x^k/k! = e^0x + .. + e^nx = 1-e^(n+1)x / 1-e^x // O(KlogK) // 0^0 = 1 // keyword: faulhaber ファウルハーバー vector SumOfPower(mint n, int K){ assert(si(fact) > K); Poly a(K+1),b(K+1); mint pw = 1; rep1(i,K+1){ pw *= n+1; a[i-1] = ifact[i]; b[i-1] = ifact[i] * pw; } auto f = b*a.inv(K+1); V res(K+1); rep(k,K+1) res[k] = f[k] * fact[k]; return res; } #line 7 "2794.cpp" void TEST(){ int N; cin >> N; V p(N); iota(all(p),0); V f(1<<(N-1)); do{ bool valid = true; rep(k,N) rep(j,k) rep(i,j) if(p[i]'; } if(f[s]) cout << " : " << f[s]; cout << endl; } cout << endl; rep(s,si(f)){ rep(i,N-1){ if(s&1< as = {-2}; rep(i,N-1) if(s[i] == '<') as.eb(i); as.eb(N); using poly = Poly; V ps; rep(i,si(as)-1){ int n = as[i+1] - as[i] - 2; poly p; rep(k,n/2+1) p.set(k,Choose(n-k, k)); ps.eb(p); } auto mul = [&](auto&& self, int l, int r) -> poly { if(r-l == 1) return ps[l]; int m = (l+r)/2; return self(self,l,m) * self(self,m,r); }; auto f = mul(mul,0,si(ps)); int A = si(as) - 2; mint res = 0; rep(k,si(f)) res += f[k] * Cat(N-A-k) * (k&1 ? -1 : 1); return res; } int main(){ cin.tie(0); ios::sync_with_stdio(false); //DON'T USE scanf/printf/puts !! cout << fixed << setprecision(20); InitFact(500000); // TEST(); int N; string s; cin >> N >> s; cout << solve(s) << endl; }