#include "bits/stdc++.h"
#ifdef DEBUG
#include "PrettyDebug.hpp"
#else
#define debug(...) [](){}()
#define debuga(...) [](){}()
#endif
#define For(i,a,b) for(int i=a;i<=b;i++)
#define Rev(i,a,b) for(int i=a;i>=b;i--)
#define Fin(file) freopen(file,"r",stdin)
#define Fout(file) freopen(file,"w",stdout)
using namespace std; typedef long long ll;
constexpr int N=305,mod=1e9+7;
namespace ModInt{
    int qpow(int x,int y){int res=1;while(y){if(y&1)res=1ll*res*x%mod;x=1ll*x*x%mod;y>>=1;}return res;}
    class Int{
        int x;
    public:
        explicit Int(int _x=0) : x(_x) {}
        Int& operator+= (const Int& O) { unsigned t=x+O.x; x=min(t,t-mod); return *this; }
        Int& operator-= (const Int& O) { unsigned t=x-O.x; x=min(t,t+mod); return *this; }
        Int& operator*= (const Int& O) { x=1ll*x*O.x%mod; return *this; }
        Int operator- () { return Int(x==0?0:mod-x); }
        friend Int operator+ (Int A,const Int& B) { return A+=B; }
        friend Int operator- (Int A,const Int& B) { return A-=B; }
        friend Int operator* (Int A,const Int& B) { return A*=B; }
        friend Int inv(const Int& A) { return Int(qpow(A.x,mod-2)); }
        template<class ...Args> void add(const Int& A,const Int& B,Args... rest) { add(rest...,Int(1ll*A.x*B.x%mod)); }
        void add(const Int& A,const Int& B) { x=(x+1ll*A.x*B.x)%mod; }
        template<class ...Args> friend Int mul(const Int& A,const Int& B,Args... rest) { return mul(rest...,Int(1ll*A.x*B.x%mod)); }
        Int mul(const Int& A,const Int& B) { return Int(1ll*A.x*B.x%mod); }
        friend istream& operator>> (istream& os,Int& O) { return os>>O.x; }
        friend ostream& operator<< (ostream& os,const Int& O){
            constexpr int LIM=1000;
            if(O.x<=LIM) os<<O.x;
            else if(O.x>=mod-LIM) os<<O.x<<"(-"<<mod-O.x<<")";
            else{
                int found=0;
                For(v,1,LIM){
                    int iv=qpow(v,mod-2);
                    For(u,1,LIM) if(1ll*u*iv%mod==O.x) { found=1; os<<O.x<<'('<<u<<"/"<<v<<')'; goto OUT; }
                    For(u,1,LIM) if(mod-1ll*u*iv%mod==O.x) { found=1; os<<O.x<<"(-"<<u<<"/"<<v<<')'; goto OUT; }
                }
                OUT: if(!found) os<<O.x<<"(?)";
            }
            return os;
        }
        friend Int qpow(Int x,int y) { return Int(qpow(x.x,y)); }
        friend Int ID(Int x) { return x.x&1?Int(mod-1):Int(1); }
        int operator()() const { return x; }
    };
    Int ID(int x) { return x&1?Int(mod-1):Int(1); }
    Int Norm(ll x) { unsigned t=x%mod; return Int(min(t,t+mod)); }
}
using namespace ModInt;
int n,K,cnt[N]; Int cp[N],ci[N],g[N],f[N][N],ans[N][N],tmp[N][N];
signed main(){
    atexit([](){cerr<<"Time = "<<clock()<<" ms"<<endl;});
    cin>>n>>K; For(i,1,n) { int x; cin>>x; cnt[x]++; }
    cp[0]=Int(1); For(i,1,n) cp[i]=cp[i-1]*Int(i);
    ci[n]=inv(cp[n]); Rev(i,n-1,0) ci[i]=ci[i+1]*Int(i+1);
    For(j,1,K) tmp[1][j]=qpow(Int(j),j-1)*ci[j];
    For(i,1,n) For(j,1,n) if(tmp[i][j]()) {
        g[j]+=tmp[i][j]*(i==1?inv(Int(j)):qpow(Int(j),i-2))*ci[i];
        if(i==n) continue;
        For(k,1,min(n-j,K)){
            tmp[i+1][j+k]-=qpow(Int(k),k-1)*ci[k]*tmp[i][j];
        }
    }
    debuga(g,1,n);
    For(k,1,n) if(cnt[k]) {
        For(i,0,n+1) For(j,0,n+1) tmp[i][j]=Int(0);
        tmp[0][0]=Int(1);
        For(i,0,cnt[k]) For(j,0,cnt[k]) if(tmp[i][j]()) {
            debug(i,j,tmp[i][j]);
            if(j==cnt[k]) f[k][i]+=tmp[i][j]*cp[cnt[k]]*ci[i];
            For(t,1,cnt[k]-j) tmp[i+1][j+t]+=Int(t)*g[t]*tmp[i][j];
        }
        debuga(f[k],1,cnt[k]);
    }
    ans[0][0]=Int(1);
    For(k,0,n-1){
        if(!cnt[k+1]) { For(i,0,n) ans[k+1][i]=ans[k][i];; continue; }
        For(i,0,n) if(ans[k][i]()) {
            For(j,1,min(n-i,cnt[k+1])) ans[k+1][i+j]+=f[k+1][j]*ans[k][i];
        }
    }
    For(k,0,n) For(i,0,n) if(ans[k][i]()) debug(k,i,ans[k][i]);
    Int Ans(0);
    For(i,1,n) Ans+=ans[n][i]*(i==1?inv(Int(n)):qpow(Int(n),i-2));
    debug(Ans);
    cout<<Ans()<<'\n';
    return 0;
}

// CONTINUE, NON-STOPPING, FOR CHARLIEY
// START TYPING IF YOU DON'T KNOW WHAT TO DO
// STOP TYPING IF YOU DON'T KNOW WHAT YOU'RE DOING

// Started Coding On: May 27 Mon, 19 : 07 : 05