#line 1 "a.cpp" #include<iostream> #include<vector> using namespace std; #line 3 "/home/kotatsugame/library/math/modint.cpp" #include<utility> template<int m> struct modint{ unsigned int x; constexpr modint()noexcept:x(){} template<typename T> constexpr modint(T x_)noexcept:x((x_%=m)<0?x_+m:x_){} constexpr unsigned int val()const noexcept{return x;} constexpr modint&operator++()noexcept{if(++x==m)x=0;return*this;} constexpr modint&operator--()noexcept{if(x==0)x=m;--x;return*this;} constexpr modint operator++(int)noexcept{modint res=*this;++*this;return res;} constexpr modint operator--(int)noexcept{modint res=*this;--*this;return res;} constexpr modint&operator+=(const modint&a)noexcept{x+=a.x;if(x>=m)x-=m;return*this;} constexpr modint&operator-=(const modint&a)noexcept{if(x<a.x)x+=m;x-=a.x;return*this;} constexpr modint&operator*=(const modint&a)noexcept{x=(unsigned long long)x*a.x%m;return*this;} constexpr modint&operator/=(const modint&a)noexcept{return*this*=a.inv();} constexpr modint operator+()const noexcept{return*this;} constexpr modint operator-()const noexcept{return modint()-*this;} constexpr modint pow(long long n)const noexcept { if(n<0)return pow(-n).inv(); modint x=*this,r=1; for(;n;x*=x,n>>=1)if(n&1)r*=x; return r; } constexpr modint inv()const noexcept { int s=x,t=m,x=1,u=0; while(t) { int k=s/t; s-=k*t; swap(s,t); x-=k*u; swap(x,u); } return modint(x); } friend constexpr modint operator+(const modint&a,const modint&b){return modint(a)+=b;} friend constexpr modint operator-(const modint&a,const modint&b){return modint(a)-=b;} friend constexpr modint operator*(const modint&a,const modint&b){return modint(a)*=b;} friend constexpr modint operator/(const modint&a,const modint&b){return modint(a)/=b;} friend constexpr bool operator==(const modint&a,const modint&b){return a.x==b.x;} friend constexpr bool operator!=(const modint&a,const modint&b){return a.x!=b.x;} friend ostream&operator<<(ostream&os,const modint&a){return os<<a.x;} friend istream&operator>>(istream&is,modint&a){long long v;is>>v;a=modint(v);return is;} }; #line 5 "a.cpp" using mint=modint<998244353>; int N,M; int P[5050]; bool vis[5050]; mint dp[5050],ep[2][2][5050]; main() { cin>>N>>M; for(int i=0;i<N;i++) { cin>>P[i]; P[i]--; } dp[0]=1; for(int i=0;i<N;i++)if(!vis[i]) { vector<int>now; now.push_back(i); do{ int u=now.back(); now.push_back(P[u]); vis[P[u]]=true; }while(now.back()!=i); now.pop_back(); int a=0; for(int j=0;j<2;j++)for(int k=0;k<=N;k++)ep[a][j][k]=0; for(int j=0;j<=N;j++) { ep[a][1][j]+=dp[j]*j; ep[a][1][j+1]+=dp[j]; } for(int id=1;id<now.size();id++) { int b=1-a; for(int j=0;j<2;j++)for(int k=0;k<=N;k++)ep[b][j][k]=0; for(int j=0;j<2;j++)for(int k=0;k<=N;k++) { if(j==0) { ep[b][1][k]+=ep[a][j][k]; ep[b][0][k]+=ep[a][j][k]*(k-2); ep[b][0][k+1]+=ep[a][j][k]; } else { ep[b][0][k]+=ep[a][j][k]*(k-1); ep[b][0][k+1]+=ep[a][j][k]; } } a=b; } for(int k=0;k<=N;k++)dp[k]=ep[a][0][k]; } cout<<dp[M]<<endl; }