#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:
https://codeforces.com/blog/entry/98663 (max+ convolution tutorial)
https://judge.yosupo.jp/submission/166484 (max+ convolution implementation)
*/
const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;
vector<pll> max_conv(vector<ll> a, vector<pll> b){
// a = concave, b = arbitrary
ll n = sz(a), m = sz(b);
vector<pll> res(n+m-1,{-inf2,-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 j = optl; j <= optr; ++j){
ll i = mid-j;
if(i >= 0 and i < n){
ll val = a[i]+b[j].ff;
if(val >= best){
best = val;
optm = j;
}
}
}
res[mid] = {best,b[optm].ss};
go(l,mid-1,optl,optm,go);
go(mid+1,r,optm,optr,go);
};
go(0,n+m-2,0,m-1,go);
return res;
}
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];
ll ans = -inf2;
vector<pll> segs;
auto upd = [&](ll l, ll r, ll v){
if(v > ans){
ans = v;
segs.clear();
segs.pb({l,r});
}
else if(v == ans){
segs.pb({l,r});
}
};
auto go = [&](ll l, ll r, auto &&go) -> pair<vector<pll>,vector<pll>>{
if(l > r) return {{{0,0}},{{0,0}}};
if(l == r){
vector<pll> v = {{0,0},{-a[l]+b[l],1}};
return {v,v};
}
ll mid = (l+r) >> 1;
auto [lp,ls] = go(l,mid,go);
auto [rp,rs] = go(mid+1,r,go);
ll siz = r-l+1;
vector<pll> cp(siz+1,{-inf2,-inf2}), cs(siz+1,{-inf2,-inf2});
rep(i,sz(lp)) amax(cp[i],lp[i]);
rep(i,sz(rs)) amax(cs[i],rs[i]);
{
vector<ll> vals;
ll sum = 0;
for(int i = l; i <= mid; ++i){
sum -= a[i];
vals.pb(b[i]);
}
sort(rall(vals));
vals.insert(vals.begin(),sum);
rep1(i,sz(vals)-1) vals[i] += vals[i-1];
auto res = max_conv(vals,rp);
rep(i,sz(res)) res[i].ss += mid-l+1;
rep(i,sz(res)) amax(cp[i],res[i]);
}
{
vector<ll> vals;
ll sum = 0;
for(int i = mid+1; i <= r; ++i){
sum -= a[i];
vals.pb(b[i]);
}
sort(rall(vals));
vals.insert(vals.begin(),sum);
rep1(i,sz(vals)-1) vals[i] += vals[i-1];
auto res = max_conv(vals,ls);
rep(i,sz(res)) res[i].ss += r-mid;
rep(i,sz(res)) amax(cs[i],res[i]);
}
if(k < sz(cp)) upd(l,l+cp[k].ss-1,cp[k].ff);
if(k < sz(cs)) upd(r-cs[k].ss+1,r,cs[k].ff);
rep(j,sz(ls)){
ll p = k-j;
if(p >= 0 and p < sz(rp)){
ll lx = mid-ls[j].ss+1;
ll rx = mid+1+rp[p].ss-1;
ll val = ls[j].ff+rp[p].ff;
upd(mid-ls[j].ss+1,mid+1+rp[p].ss-1,ls[j].ff+rp[p].ff);
}
}
rep1(i,sz(cp)-1) assert(cp[i].ss >= cp[i-1].ss);
rep1(i,sz(cs)-1) assert(cs[i].ss >= cs[i-1].ss);
return {cp,cs};
};
go(1,n,go);
cout << ans << endl;
}
int main()
{
fastio;
int t = 1;
// cin >> t;
rep1(i, t) {
solve(i);
}
return 0;
}
