#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl
#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)
template<typename T>
void amin(T &a, T b) {
a = min(a,b);
}
template<typename T>
void amax(T &a, T b) {
a = max(a,b);
}
#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif
/*
refs:
edi
*/
const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;
void solve(int test_case)
{
ll n,k; cin >> n >> k;
vector<ll> a(n+5), b(n+5);
rep1(i,n) cin >> a[i];
rep1(i,n) cin >> b[i];
vector<ll> p(n+5);
rep1(i,n) p[i] = p[i-1]+a[i];
multiset<ll> ms1,ms2;
ll curr_sum = 0;
ll lx = 1, rx = 0;
auto transfer = [&](){
while(!ms2.empty() and sz(ms1) < k){
curr_sum += *ms2.rbegin();
ms1.insert(*ms2.rbegin());
ms2.erase(--ms2.end());
}
while(sz(ms1) > k){
ll x = *ms1.begin();
curr_sum -= x;
ms1.erase(ms1.begin());
ms2.insert(x);
}
if(ms2.empty()) return;
while(true){
ll mn1 = *ms1.begin(), mx2 = *ms2.rbegin();
if(mn1 >= mx2) break;
ms1.erase(ms1.find(mn1));
ms2.erase(ms2.find(mx2));
ms1.insert(mx2);
ms2.insert(mn1);
curr_sum += mx2-mn1;
}
};
auto ins = [&](ll i){
ms1.insert(b[i]);
curr_sum += b[i];
transfer();
};
auto del = [&](ll i){
if(ms1.find(b[i]) != ms1.end()){
ms1.erase(ms1.find(b[i]));
curr_sum -= b[i];
}
else{
ms2.erase(ms2.find(b[i]));
}
transfer();
};
auto f = [&](ll l, ll r){
if(r-l+1 < k) return -inf2;
// expand
while(rx < r){
rx++;
ins(rx);
}
while(lx > l){
lx--;
ins(lx);
}
// contract
while(rx > r){
del(rx);
rx--;
}
while(lx < l){
del(lx);
lx++;
}
ll sum = -(p[r]-p[l-1]);
sum += curr_sum;
return sum;
};
ll ans = -inf2;
auto go = [&](ll l, ll r, ll optl, ll optr, auto &&go) -> void{
if(l > r) return;
ll mid = (l+r) >> 1;
ll best = -inf2, optm = -1;
for(int i = optl; i <= optr; ++i){
ll cost = f(mid,i);
if(cost >= best){
best = cost;
optm = i;
}
}
amax(ans,best);
go(l,mid-1,optl,optm,go);
go(mid+1,r,optm,optr,go);
};
go(1,n-k+1,1,n,go);
cout << ans << endl;
}
int main()
{
fastio;
int t = 1;
// cin >> t;
rep1(i, t) {
solve(i);
}
return 0;
}
