#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
ll n,m;
ll a[2005],b[2005];
ll pref[2005],suff[2005];
ll mod=1e9+7;
ll jawab;
vector <ll> ans;
ll fact (ll nn){
if (nn==0) return 1;
return nn%mod*fact(nn-1)%mod;
}
ll kali (ll x, ll y){
return (x*y)%mod;
}
ll simpan=1;
void fexpo(ll x, ll y){
if(y == 0) return;
if (y==1) {
simpan=kali(simpan,x);
return;
}
if (y%2==0){
fexpo(kali(x,x),y/2);
}
else{
simpan=kali(simpan,x);
fexpo(kali(x,x),(y-1)/2);
}
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
//fexpo(fact(1950), mod - 2);
//fexpo(fact(2000), mod - 2);
cin>>n>>m;
for (int i=1;i<=n;i++){
cin>>a[i];
pref[i]=max(pref[i-1],a[i]);
// cout<<pref[i]<<endl;
}
for (int i=1;i<=n;i++){
suff[i]=max(suff[i-1],a[n-i+1]);
}
// for (int i=1;i<=n;i++) cout<<pref[i]<<" "<<suff[i]<<":::"<<i<<endl;
for (int i=1;i<=m;i++){
cin>>b[i];
}
if (n<m) {
cout<<0;
return 0;
}
ll tes=1;
ll u=m-1;
fexpo(fact(u)%mod,mod-2);
tes*=simpan%mod;
simpan=1;
fexpo(fact(n-m)%mod,mod-2);
tes*=simpan%mod*fact(n-1)%mod;
tes%=mod;
cout<<tes;
}
