#include<bits/stdc++.h>
using namespace std;
const int mod=1000000007;
typedef long long ll;
int n,a[200005];
ll jc[200005],iv[200005],B;
void init(){
	jc[0]=iv[0]=jc[1]=iv[1]=1;
	for(int i=2;i<=200000;++i){
		jc[i]=jc[i-1]*i%mod;
		iv[i]=(mod-mod/i)*iv[mod%i]%mod;
	}
	for(int i=1;i<=200000;++i)iv[i]=iv[i-1]*iv[i]%mod;
}
ll C(int n,int m){
	if(m<0||m>n)return 0;
	return jc[n]*iv[m]%mod*iv[n-m]%mod;
}
int c[200005],m;
int main(){
	init();
	scanf("%d%lld",&n,&B);
	for(int i=1;i<=n;++i)scanf("%d",&a[i]);
	sort(a+1,a+1+n);a[0]=-1;
	for(int i=1;i<=n;++i){
		if(a[i]!=a[i-1]){
			m++;
			c[m]=1;
		}
		else c[m]++;
	}
	ll f=B*jc[c[m]]%mod,g=B*jc[c[m]]%mod;
	ll d=c[m];
	for(int i=m-1;i>=1;--i){
		g=(B*jc[c[i]]%mod*C(d+c[i]-1,c[i]-1)%mod*(f+g)%mod+jc[c[i]]*C(d+c[i]-1,c[i])%mod*g%mod)%mod;
		f=(B*jc[c[i]]%mod*C(d+c[i]-1,c[i]-1)%mod*f%mod+jc[c[i]]*C(d+c[i]-1,c[i])%mod*f%mod)%mod;
		d+=c[i];
	}
	printf("%lld",g);
	return 0;
}