#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 1e5 + 5;
int n, k;
int a[N], b[N], c[N];
bool st[N];
void solve()
{
	cin >> n >> k;
	for (int i = 1; i <= n; i++)
	{
		cin >> a[i];
	}
	for (int i = 1; i <= n; i++)
	{
		cin >> b[i];
	}
	sort(a + 1, a + 1 + n, [&](int x, int y) {return x > y;});
	sort(b + 1, b + 1 + n, [&](int x, int y) {return x > y;});
	for (int i = 1; i <= n; i++)
	{
		c[i] = a[i] - b[i];
	}
	sort(c + 1, c + 1 + n, [&](int x, int y) {return x > y;});
	map<int, int>mp;
	for (int i = 1; i <= k; i++)
		mp[c[i]]++;
	for (int i = 1; i <= n; i++)
	{
		int cha = a[i] - b[i];
		if (mp.count(cha))
		{
			st[i] = true;
			mp[cha]--;
			if (mp[cha] == 0) mp.erase(cha);
		}
	}
	int L = 1, R = 1;
	vector<int>aa, bb;
	int op = 0;
	while (L <= n || R <= n)
	{
		if (!op)
		{
			if (!st[R] && R <= n)
			{
				if (a[L] < b[R])
					R++;
				else aa.push_back(a[L++]);
			}
			else
			{
				if (L <= n && a[L] >= b[R])
					aa.push_back(a[L++]);
				else R++;
			}
		}
		else
		{
			if (!st[L] && L <= n)
			{
				if (a[L] > b[R])
					L++;
				else bb.push_back(b[R++]);
			}
			else
			{
				if (R <= n && a[L] <= b[R])
					bb.push_back(b[R++]);
				else L++;
			}
		}
		op ^= 1;
	}
	int ans = 0;
	for (int i = 0; i < min((int)(aa.size()), k); i++)
	{
		ans += aa[i];
	}
	for (int i = 0; i < min((int)(bb.size()), k); i++)
	{
		ans -= bb[i];
	}
	cout << ans << endl;
}

signed main()
{
	ios::sync_with_stdio(false);
	cin.tie(0), cout.tie(0);
	int test = 1;
	// cin >> test;
	for (int i = 1; i <= test; i++)
	{
		solve();
	}
	return 0;
}