#include <math.h>
#include <stdio.h>
#include <string.h>
#include <vector>
#include <string>
#include <queue>
#include <map>
#include <algorithm>
#include <cmath>
#include <iostream>
#include <sstream>
#include <set>
using namespace std;
const int mmod = 1000000007;
int calc(vector<int> a, vector<int> b, int k, int ue, int le) {
int n = a.size();
vector<int> cnt(n);
for (int i=0; i<k; i++)
for (int j=0; j<n; j++)
if (a[i]+b[j] >= ue) cnt[i] = j+1;
for (int i=k; i<n; i++)
for (int j=0; j<n; j++)
if (a[i]+b[j] > le) cnt[i] = j+1;
vector<int> prv(n+1);
prv[0] = 1;
if (k % 2) prv[0] = -1;
for (int i=n-1; i>=0; i--) {
vector<int> nxt(n+1);
for (int j=0; j<n; j++) {
int mult = max(0, cnt[i] - j);
nxt[j+1] = (nxt[j+1] - 1LL * mult * prv[j]) % mmod;
if (i >= k) {
nxt[j] = (nxt[j] + prv[j]) % mmod;
}
}
for (int j=0; j<=n; j++)
prv[j] = (nxt[j] + mmod) % mmod;
}
int ret = 0;
for (int i=0; i<=n; i++) {
int now = prv[i];
for (int j=1; j<=n-i; j++)
now = (now * 1LL * j) % mmod;
ret = (ret + now) % mmod;
}
return ret;
}
int main()
{
int n, k;
cin >> n >> k;
vector<int> a(n), b(n);
for (int i=0; i<n; i++) cin >> a[i];
for (int i=0; i<n; i++) cin >> b[i];
sort(a.rbegin(), a.rend());
sort(b.rbegin(), b.rend());
int res = 0;
for (int x = 1; x <= 2000; x++) {
res += calc(a, b, k, x, x);
res -= calc(a, b, k, x+1, x);
res %= mmod;
res = (res + mmod) % mmod;
}
cout << res << endl;
}
