#pragma GCC optimize ("Ofast") #include using namespace std; #define MD (1000000007U) void*wmem; char memarr[96000000]; struct Modint{ unsigned val; Modint(){ val=0; } Modint(int a){ val = ord(a); } Modint(unsigned a){ val = ord(a); } Modint(long long a){ val = ord(a); } Modint(unsigned long long a){ val = ord(a); } inline unsigned ord(unsigned a){ return a%MD; } inline unsigned ord(int a){ a %= (int)MD; if(a < 0){ a += MD; } return a; } inline unsigned ord(unsigned long long a){ return a%MD; } inline unsigned ord(long long a){ a %= (int)MD; if(a < 0){ a += MD; } return a; } inline unsigned get(){ return val; } inline Modint &operator++(){ val++; if(val >= MD){ val -= MD; } return *this; } inline Modint &operator--(){ if(val == 0){ val = MD - 1; } else{ --val; } return *this; } inline Modint operator++(int a){ Modint res(*this); val++; if(val >= MD){ val -= MD; } return res; } inline Modint operator--(int a){ Modint res(*this); if(val == 0){ val = MD - 1; } else{ --val; } return res; } inline Modint &operator+=(Modint a){ val += a.val; if(val >= MD){ val -= MD; } return *this; } inline Modint &operator-=(Modint a){ if(val < a.val){ val = val + MD - a.val; } else{ val -= a.val; } return *this; } inline Modint &operator*=(Modint a){ val = ((unsigned long long)val*a.val)%MD; return *this; } inline Modint &operator/=(Modint a){ return *this *= a.inverse(); } inline Modint operator+(Modint a){ return Modint(*this)+=a; } inline Modint operator-(Modint a){ return Modint(*this)-=a; } inline Modint operator*(Modint a){ return Modint(*this)*=a; } inline Modint operator/(Modint a){ return Modint(*this)/=a; } inline Modint operator+(int a){ return Modint(*this)+=Modint(a); } inline Modint operator-(int a){ return Modint(*this)-=Modint(a); } inline Modint operator*(int a){ return Modint(*this)*=Modint(a); } inline Modint operator/(int a){ return Modint(*this)/=Modint(a); } inline Modint operator+(long long a){ return Modint(*this)+=Modint(a); } inline Modint operator-(long long a){ return Modint(*this)-=Modint(a); } inline Modint operator*(long long a){ return Modint(*this)*=Modint(a); } inline Modint operator/(long long a){ return Modint(*this)/=Modint(a); } inline Modint operator-(void){ Modint res; if(val){ res.val=MD-val; } else{ res.val=0; } return res; } inline operator bool(void){ return val!=0; } inline operator int(void){ return get(); } inline operator long long(void){ return get(); } inline Modint inverse(){ int a = val; int b = MD; int u = 1; int v = 0; int t; Modint res; while(b){ t = a / b; a -= t * b; swap(a, b); u -= t * v; swap(u, v); } if(u < 0){ u += MD; } res.val = u; return res; } inline Modint pw(unsigned long long b){ Modint a(*this); Modint res; res.val = 1; while(b){ if(b&1){ res *= a; } b >>= 1; a *= a; } return res; } inline bool operator==(int a){ return ord(a)==val; } inline bool operator!=(int a){ return ord(a)!=val; } } ; inline Modint operator+(int a, Modint b){ return Modint(a)+=b; } inline Modint operator-(int a, Modint b){ return Modint(a)-=b; } inline Modint operator*(int a, Modint b){ return Modint(a)*=b; } inline Modint operator/(int a, Modint b){ return Modint(a)/=b; } inline Modint operator+(long long a, Modint b){ return Modint(a)+=b; } inline Modint operator-(long long a, Modint b){ return Modint(a)-=b; } inline Modint operator*(long long a, Modint b){ return Modint(a)*=b; } inline Modint operator/(long long a, Modint b){ return Modint(a)/=b; } inline int my_getchar(){ static char buf[1048576]; static int s = 1048576; static int e = 1048576; if(s == e && e == 1048576){ e = fread(buf, 1, 1048576, stdin); s = 0; } if(s == e){ return EOF; } return buf[s++]; } inline void rd(int &x){ int k; int m=0; x=0; for(;;){ k = my_getchar(); if(k=='-'){ m=1; break; } if('0'<=k&&k<='9'){ x=k-'0'; break; } } for(;;){ k = my_getchar(); if(k<'0'||k>'9'){ break; } x=x*10+k-'0'; } if(m){ x=-x; } } inline int rd(char c[]){ int i; int sz = 0; for(;;){ i = my_getchar(); if(i!=' '&&i!='\n'&&i!='\r'&&i!='\t'&&i!=EOF){ break; } } c[sz++] = i; for(;;){ i = my_getchar(); if(i==' '||i=='\n'||i=='\r'||i=='\t'||i==EOF){ break; } c[sz++] = i; } c[sz]='\0'; return sz; } inline void rd(string &x){ char*buf = (char *)wmem; rd(buf); x = buf; } struct MY_WRITER{ char buf[1048576]; int s; int e; MY_WRITER(){ s = 0; e = 1048576; } ~MY_WRITER(){ if(s){ fwrite(buf, 1, s, stdout); } } } ; MY_WRITER MY_WRITER_VAR; void my_putchar(int a){ if(MY_WRITER_VAR.s == MY_WRITER_VAR.e){ fwrite(MY_WRITER_VAR.buf, 1, MY_WRITER_VAR.s, stdout); MY_WRITER_VAR.s = 0; } MY_WRITER_VAR.buf[MY_WRITER_VAR.s++] = a; } inline void wt_L(char a){ my_putchar(a); } inline void wt_L(int x){ int s=0; int m=0; char f[10]; if(x<0){ m=1; x=-x; } while(x){ f[s++]=x%10; x/=10; } if(!s){ f[s++]=0; } if(m){ my_putchar('-'); } while(s--){ my_putchar(f[s]+'0'); } } inline void wt_L(Modint x){ int i; i = (int)x; wt_L(i); } int N; string s; string ours = "yukicoder"; char opr[100]; Modint f[100000+10][12]; vector dictionary; int main(){ int i; wmem = memarr; rd(N); rd(s); dictionary.push_back(ours); int ns = ours.length(); for(i=(0);i<(ns);i++){ memcpy(opr, ours.c_str(), ns); opr[ns] = 0; opr[i] = '?'; dictionary.push_back((string)(opr)); } int ms = dictionary.size(); Modint ans; ans = 0; for(i=(0);i<(ms);i++){ int j; for(j=(0);j<(N+2);j++){ int k; for(k=(0);k<(ns+2);k++){ f[j][k] = 0; } } f[0][0] = 1; for(j=(0);j<(N);j++){ int k; for(k=(0);k<(ns+1);k++){ f[j+1][k] += f[j][k]; if(k < ns && dictionary[i][k] == s[j]){ f[j+1][k+1] += f[j][k]; } } } ans += f[N][ns]; } wt_L(ans); wt_L('\n'); return 0; } // cLay version 20210405-1 // --- original code --- // //no-unlocked // int N; // string s; // string ours = "yukicoder"; // char opr[1d2]; // Modint f[1d5+10][12]; // vector dictionary; // { // rd(N, s); // dictionary.push_back(ours); // int ns = ours.length(); // rep(i, ns){ // memcpy(opr, ours.c_str(), ns); // opr[ns] = 0; // opr[i] = '?'; // dictionary.push_back((string)(opr)); // } // int ms = dictionary.size(); // Modint ans; // ans = 0; // rep(i, ms){ // rep(j, N+2) rep(k, ns+2) f[j][k] = 0; // f[0][0] = 1; // rep(j, N) { // rep(k, ns+1){ // f[j+1][k] += f[j][k]; // if(k < ns && dictionary[i][k] == s[j]) f[j+1][k+1] += f[j][k]; // } // } // ans += f[N][ns]; // } // wt(ans); // }