#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define X first #define Y second #define pb push_back #define rep(X,Y) for (int X = 0;X < (int)(Y);++X) #define reps(X,S,Y) for (int X = (int)(S);X < (int)(Y);++X) #define rrep(X,Y) for (int X = (int)(Y)-1;X >=0;--X) #define rreps(X,S,Y) for (int X = (int)(Y)-1;X >= (int)(S);--X) #define repe(X,Y) for (X = 0;X < (Y);++X) #define peat(X,Y) for (;X < (Y);++X) #define all(X) X.begin(),X.end() #define rall(X) X.rbegin(),X.rend() #define eb emplace_back #define UNIQUE(X) X.erase(unique(all(X)),X.end()) #define Endl endl #define NL <<"\n" #define cauto const auto using namespace std; using ll=long long; using pii=pair; using pll=pair; template using vv=vector>; template inline bool MX(T &l,const T &r){return l inline bool MN(T &l,const T &r){return l>r?l=r,1:0;} //#undef NUIP #ifdef NUIP #include "benri.h" #else #define out(args...) #endif void ouT(ll x,int d=3){auto re=to_string(x);if((int)re.size()>d) re=x>0?"oo":"-oo";cout<vector table(int n, T v){ return vector(n, v);} template auto table(int n, Args... args){auto val = table(args...); return vector(n, move(val));} #endif template pair operator+(const pair &p,const pair &q){ return {p.X+q.X,p.Y+q.Y};} template pair& operator+=(pair &p,const pair &q){ p.X+=q.X; p.Y+=q.Y; return p;} template pair operator-(const pair &p,const pair &q){ return {p.X-q.X,p.Y-q.Y};} template pair& operator-=(pair &p,const pair &q){ p.X-=q.X; p.Y-=q.Y; return p;} template istream& operator>>(istream &is, pair &p){ is>>p.X>>p.Y; return is;} template T read(){ T re; cin>>re; return re;} template T read(const T &dec){ T re; cin>>re; return re-dec;} template vector readV(const int sz){ vector re(sz); for(auto &x:re) x=read(); return re;} template vector readV(const int sz, const T &dec){ vector re(sz); for(auto &x:re) x=read(dec); return re;} vv readG(const int &n,const int &m){ vv g(n); rep(_,m){ cauto a=read(1),b=read(1); g[a].pb(b); g[b].pb(a);} return g;} vv readG(const int &n){ return readG(n,n-1);} vv readD(const int &n,const int &m){ vv g(n); rep(_,m){ cauto a=read(1),b=read(1); g[a].pb(b); } return g;} vv readD(const int &n){ return readD(n,n-1);} template vv> readG(const int &n,const int &m){ vv> g(n); rep(_,m){ cauto a=read(1),b=read(1); cauto c=read(); g[a].eb(b,c); g[b].eb(a,c);} return g;} template vv> readG(const int &n){ return readG(n,n-1);} template vv> readD(const int &n,const int &m){ vv> g(n); rep(_,m){ cauto a=read(1),b=read(1); cauto c=read(); g[a].eb(b,c); } return g;} template vv> readD(const int &n){ return readD(n,n-1);} #ifdef __cpp_deduction_guides template vector readT(int n, T v){ return readV(n,v);} template auto readT(int n, Args... args){ vector re(1,readT(args...));rep(_,n-1) re.eb(readT(args...)); return re;} template void read_tuple_impl(istream &is, Tuple& t, index_sequence){((is >> get(t)), ...);} template auto& operator>>(istream &is, tuple& t){ read_tuple_impl(is, t, index_sequence_for{}); return is;} template bool erase(multiset &st, const T &v){if(cauto it=st.find(v); it==st.end()) return false; else{ st.erase(it); return true;}} #endif #ifdef __cpp_init_captures template void addadd(T& t1, const T& t2, integer_sequence){ cauto l = { (get(t1) += get(t2), 0)... }; (void)l;} template tuple& operator += (tuple& lhs, const tuple& rhs){ addadd(lhs, rhs, index_sequence_for{}); return lhs;} template tuple operator +(tuple lhs, const tuple& rhs){ return lhs += rhs;} template void subsub(T& t1, const T& t2, integer_sequence){ cauto l = { (get(t1) -= get(t2), 0)... }; (void)l;} template tuple& operator -= (tuple& lhs, const tuple& rhs){ subsub(lhs, rhs, index_sequence_for{}); return lhs;} template tuple operator - (tuple lhs, const tuple& rhs){ return lhs -= rhs;} #endif #define TT cauto TTT=read();rep(_,TTT) struct sorted_impl{templatefriend vectoroperator-(vectora,sorted_impl){sort(all(a));return a;}friend string operator-(string a,sorted_impl){sort(all(a));return a;}}sorted;struct reversed_impl{templatefriend vectoroperator-(vector a,reversed_impl){reverse(all(a));return a;}friend string operator-(string a,reversed_impl){reverse(all(a));return a;}}reversed;struct distinct_impl{templatefriend vectoroperator-(vector a,distinct_impl){sort(all(a));UNIQUE(a);return a;}}distinct;templatestruct sortedWith{const S f;sortedWith(const S &f):f(f){}templatefriend vectoroperator-(vector a,const sortedWith&b){sort(all(a),[&](cauto&i,cauto&j){return b.f(i)int operator/(const T&v,const vector&vs){return lower_bound(all(vs),v)-vs.begin();} vector Inds(const int n){vector inds(n);iota(all(inds),0);return inds;} const ll MOD=998244353; ll modpow_(ll r,ll n,ll m=MOD){ ll re=1,d=r%m; if(n<0)(n%=m-1)+=m-1; for(;n;n/=2){ if(n&1)(re*=d)%=m; (d*=d)%=m; } return re; } template struct ModInt{ int v; ModInt(int v=0):v(v){} ModInt operator+(const ModInt &n)const{return v+n.v=mod) v-=mod; return *this;} ModInt& operator-=(const ModInt &n){v-=n.v; if(v<0) v+=mod; return *this;} ModInt& operator*=(const ModInt &n){v=ll(v)*n.v%mod; return *this;} ModInt& operator/=(const ModInt &n){v=ll(v)*modpow_(n.v,-1,mod)%mod; return *this;} ModInt& operator+=(const int &n){v+=n; if(v>=mod) v-=mod; return *this;} ModInt& operator-=(const int &n){v-=n; if(v<0) v+=mod; return *this;} ModInt& operator*=(const ll &n){v=ll(v)*n%mod; return *this;} ModInt& operator/=(const ll &n){v=ll(v)*modpow_(n,-1,mod)%mod; return *this;} bool operator==(const ModInt &n)const{return v==n.v;}; bool operator!=(const ModInt &n)const{return v!=n.v;}; ModInt& operator++(){ return operator+=(1); } ModInt& operator--(){ return operator-=(1); } ModInt operator++(int i){ ModInt tmp(*this); operator++(); return tmp; } ModInt operator--(int i){ ModInt tmp(*this); operator--(); return tmp; } }; #ifdef NUIP class MINT_FRAC____{ public: unordered_map dict; MINT_FRAC____(int n){ rep(p,n+1)reps(q,1,n+1)if(__gcd(p,q)==1){ dict[int(1ll*p*modpow_(q,-1)%MOD)]=pii(p,q); dict[int(MOD-1ll*p*modpow_(q,-1)%MOD)]=pii(-p,q); } } } Il1Il1Il1(1000); template ostream& operator<<(ostream &os,const ModInt &n){if(Il1Il1Il1.dict.count(n.v)) os< ostream& operator<<(ostream &os,const ModInt &n){return os< ModInt operator+(const ll &n,const ModInt &m){return m.v+n ModInt operator-(const ll &n,const ModInt &m){return n-m.v<0 ? n-m.v+mod : n-m.v;} template ModInt operator*(const ll &n,const ModInt &m){return ll(m.v)*(n%mod)%mod;} template ModInt operator/(const ll &n,const ModInt &m){return ModInt(n%mod)/m;} typedef ModInt mint; template ModInt modpow(ModInt r,ll n){ ModInt re(1); if(n<0)(n%=mod-1)+=mod-1; for(;n;n/=2){if(n&1) re*=r; r*=r;} return re;} vector fact,finv,inv; mint comb(ll n,ll r){ if(n &re,int n){ re.resize(n+1); re[1]=1; for(int i=2;i<=n;++i)re[i]=re[MOD%i]*(MOD-MOD/i);} void Facts(vector &re,int n){ re.resize(n+1); re[0]=1; rep(i,n)re[i+1]=re[i]*(i+1);} void Factinvs(vector &re,const vector &inv,int n){ re.resize(n+1); re[0]=1; rep(i,n)re[i+1]=re[i]*inv[i+1];} public: Doralion(int n){ Modinvs(inv,n); Facts(fact,n); Factinvs(finv,inv,n);} } doralion(1123456); using pmm=pair; mint modpow(ll r,ll n){ return (int)modpow_(r,n);} int main(){ ios_base::sync_with_stdio(false); cin.tie(0); cout<(); vector pw(n+1,1); rep(i,n) pw[i+1]=pw[i]*25; int cnt=0; mint re=0; rep(i,n){ if(cnt==0){ if(s[i]!='a'){ re+=pw[n-1-i]; re+=pw[n-2-i]*(n-1-i)*(s[i]-'a'-1); } }else if(cnt==1){ if(s[i]!='a') re+=pw[n-1-i]*(s[i]-'a'-1); }else break; out(i,re,1); if(s[i]=='a') ++cnt; } cout<