#include<bits/stdc++.h>
#define int long long
#define rep(i,j,k) for(int i=j;i<=k;i++)
#define per(i,j,k) for(int i=j;i>=k;i--) 
using namespace std;
const int N=305,mod=1e9+7;
int n,K,s,ans,pw[N][N],c[N][N],zs[N],f[N][N],f1[N][N],g[N],xs[N],inv[N];
signed main(){
	ios::sync_with_stdio(false);
	cin>>n>>K,inv[1]=1;
	rep(i,2,n) inv[i]=(mod-mod/i)*inv[mod%i]%mod;
	rep(i,1,n){pw[i][0]=1; rep(j,1,n) pw[i][j]=pw[i][j-1]*i%mod;}
	rep(i,0,n){c[i][0]=1; rep(j,1,i) c[i][j]=(c[i-1][j]+c[i-1][j-1])%mod;}
	rep(i,1,n){int col; cin>>col,zs[col]++;}
	f[0][0]=f1[0][0]=g[0]=1;
	rep(i,1,n) rep(j,1,i){
		rep(k,1,min(K,i)) f[i][j]=(f[i][j]+f[i-k][j-1]*(k==1?1:pw[k][k-2])%mod*c[i-1][k-1]%mod*k)%mod;
		xs[i]=(xs[i]+(((j-1)&1)?mod-1:1)*(j==1?inv[i]:pw[i][j-2])%mod*f[i][j])%mod;
	}
	rep(i,1,n) rep(j,1,i) rep(k,1,i) f1[i][j]=(f1[i][j]+f1[i-k][j-1]*xs[k]%mod*c[i-1][k-1]%mod*k)%mod;
	rep(i,1,n) if(zs[i]){
		per(j,s,0){
			rep(k,1,zs[i]) g[j+k]=(g[j+k]+g[j]*f1[zs[i]][k])%mod; 
			g[j]=0;
		}s+=zs[i];
	}
	rep(i,1,n) ans=(ans+g[i]*(i==1?inv[n]:pw[n][i-2]))%mod;
	cout<<ans;
}