#include<bits/stdc++.h>
using namespace std;
#define int long long
#define inf (int)2e18
#define nl '\n'
const int N = 250001;
int k, cl, cr, sum, ans = -inf;
int c[N], s[N];
multiset<int> in, out;
void add(int i){
sum -= c[i];
int x = s[i];
auto it = in.begin();
if(in.size() < k){
in.insert(x);
sum += x;
}
else if(x > *it){
sum -= *it;
out.insert(*it);
in.erase(it);
in.insert(x);
sum += x;
}
else{
out.insert(x);
}
}
void del(int i){
sum += c[i];
int x = s[i];
if(out.find(x) != out.end()){
out.erase(out.find(x));
}
else{
in.erase(in.find(x));
sum -= x;
if(!out.empty()){
auto it = prev(out.end());
sum += *it;
in.insert(*it);
out.erase(it);
}
}
}
void seg(int l, int r){
while(cl < l){
del(cl);
cl++;
}
while(cl > l){
cl--;
add(cl);
}
while(cr < r){
cr++;
add(cr);
}
while(cr > r){
del(cr);
cr--;
}
}
void solve(int l, int r, int opl, int opr){
if(l > r) return;
int m = (l+r)/2;
int ogl = cl, ogr = cr;
seg(m, max(m, opl));
int mx = -inf, op = opr;
if(cr - m + 1 >= k){
mx = sum;
op = cr;
}
while(cr < opr){
cr++;
add(cr);
if(cr-m+1 < k) continue;
if(mx < sum){
mx = sum;
op = cr;
}
}
ans = max(ans, mx);
solve(l, m-1, opl, op);
solve(m+1, r, op, opr);
seg(ogl, ogr);
}
void solve(){
int n;
cin>>n>>k;
for(int i = 1; i <= n; i++) cin>>c[i];
for(int i = 1; i <= n; i++) cin>>s[i];
cl = 1, cr = n;
for(int i = 1; i <= n; i++) add(i);
solve(1, n, 1, n);
cout<<ans;
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(NULL);cout.tie(NULL);
int t = 1;
//cin>>t;
while(t--) solve();
return 0;
}
