#include<bits/stdc++.h>
using namespace std;
const int N=305,mod=1e9+7;
int n,k,col[N],cnt[N],f[2][N],g[N][N],h[N][N],pw[N][N],c[N][N],hv[N];
int power(int a,int b){int res=1;for(;b;b>>=1){if(b&1)res=1ll*res*a%mod;a=1ll*a*a%mod;}return res;}
int gv(int x){if(x==1)return 1;return pw[x][x-2];}
int main()
{
	for(int i=1;i<N;i++)
	{
		pw[i][0]=1;
		for(int j=1;j<N;j++)pw[i][j]=1ll*pw[i][j-1]*i%mod;
	}
	for(int i=0;i<N;i++)
	{
		c[i][0]=1;
		for(int j=1;j<=i;j++)c[i][j]=(c[i-1][j]+c[i-1][j-1])%mod;
	}
	scanf("%d %d",&n,&k);
	for(int i=1;i<=n;i++)scanf("%d",&col[i]),cnt[col[i]]++;
	int p=1,q=0;f[0][0]=1;
	for(int t=1;t<=n;t++)if(cnt[t])
	{
		memset(h,0,sizeof(h)),memset(g,0,sizeof(g)),memset(hv,0,sizeof(hv));
		h[0][0]=mod-1;
		for(int i=1;i<=cnt[t];i++)for(int j=1;j<=i;j++)for(int l=1;l<=min(i,k);l++)h[i][j]=(h[i][j]-1ll*h[i-l][j-1]*c[i-1][l-1]%mod*gv(l)%mod*l%mod+mod)%mod;
		for(int i=1;i<=cnt[t];i++)for(int j=1;j<=i;j++)hv[i]=(hv[i]+1ll*h[i][j]*power(i,(j-2+mod-1)%(mod-1)))%mod;
		g[0][0]=1;
		for(int i=1;i<=cnt[t];i++)for(int j=1;j<=i;j++)for(int l=1;l<=i;l++)g[i][j]=(g[i][j]+1ll*g[i-l][j-1]*c[i-1][l-1]%mod*hv[l]%mod*l)%mod;
		memset(f[p],0,sizeof(f[p]));
		// cout<<"h3="<<h[3][1]<<" "<<h[3][2]<<" "<<h[3][3]<<endl;
		// for(int j=1;j<=cnt[t];j++)printf("%d ",hv[j]);printf("\n");
		// for(int j=1;j<=cnt[t];j++)printf("%d ",g[cnt[t]][j]);printf("\n");
		for(int j=0;j<=n;j++)if(f[q][j])
		{
			for(int l=1;l<=cnt[t];l++)
			{
				f[p][j+l]=(f[p][j+l]+1ll*f[q][j]*g[cnt[t]][l])%mod;
			}
		}
		swap(p,q);
	}
	int ans=0;
	// cout<<f[q][1]<<" "<<f[q][2]<<" "<<f[q][3]<<" "<<f[q][4]<<" "<<f[q][5]<<endl;
	for(int i=1;i<=n;i++)ans=(ans+1ll*f[q][i]*power(n,(i-2+mod-1)%(mod-1)))%mod;
	printf("%d\n",ans);
	return 0;
}