#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(x) 42
#endif
/*
*/
const int MOD = 1e9 + 7;
const int N = 2e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;
vector<int> oa(N);
struct wavelet_tree{
struct node{
node *l, *r;
vector<int> b;
vector<ll> pref;
};
node* root;
int siz;
wavelet_tree(){
}
node* build(vector<int> &a, vector<int> inds, int l, int r){
if(l > r) return NULL;
int mid = (l+r) >> 1;
vector<int> b(sz(inds)+1);
vector<int> la,ra;
rep(i,sz(inds)){
int x = a[inds[i]];
b[i+1] = b[i]+(x <= mid);
if(x <= mid){
la.pb(inds[i]);
}
else{
ra.pb(inds[i]);
}
}
node* curr = new node();
curr->b = b;
vector<ll> pref;
pref.pb(0);
trav(i,inds){
pref.pb(pref.back()+oa[i]);
}
curr->pref = pref;
if(l != r){
curr->l = build(a,la,l,mid);
curr->r = build(a,ra,mid+1,r);
}
return curr;
}
void build(vector<int> &a, int mx_siz){
siz = mx_siz;
vector<int> inds;
rep(i,sz(a)) inds.pb(i);
root = build(a,inds,0,siz);
}
int kth(node* u, int lx, int rx, int l, int r, int k){
if(lx == rx){
return lx;
}
int mid = (lx+rx) >> 1;
auto &b = u->b;
int cnt = b[r]-b[l-1];
if(k <= cnt){
// go left
return kth(u->l,lx,mid,b[l-1]+1,b[r],k);
}
else{
// go right
return kth(u->r,mid+1,rx,l-b[l-1],r-b[r],k-cnt);
}
}
int kth(int l, int r, int k){
return kth(root,0,siz,l+1,r+1,k);
}
pll get(node* u, int lx, int rx, int vl, int vr, int l, int r){
if(lx > vr or rx < vl) return {0,0};
if(!u) return {0,0};
if(lx > rx) return {0,0};
if(lx >= vl and rx <= vr){
return {r-l+1,u->pref[r]-u->pref[l-1]};
}
int mid = (lx+rx) >> 1;
auto &b = u->b;
pll p1 = get(u->l,lx,mid,vl,vr,b[l-1]+1,b[r]);
pll p2 = get(u->r,mid+1,rx,vl,vr,l-b[l-1],r-b[r]);
return {p1.ff+p2.ff,p1.ss+p2.ss};
}
pll get(int l, int r, int k){
return get(root,0,siz,k,siz,l+1,r+1);
}
};
vector<pii> a(N);
vector<int> c;
wavelet_tree wt;
ll ans = -inf2;
int n,m;
ll get_cost(int l, int r){
int len = r-l+1;
if(len < m) return -inf2;
int k = len-m+1;
int kth = wt.kth(l,r,k);
auto [cnt,sum] = wt.get(l,r,kth);
assert(cnt >= m);
ll extra = cnt-m;
sum -= extra*c[kth];
sum -= 2*(a[r].ff-a[l].ff);
return sum;
}
void go(int l, int r, int optl, int optr){
if(l > r) return;
int mid = (l+r) >> 1;
ll best = -inf2;
int opt_mid = optr;
for(int j = optl; j <= optr; ++j){
if(mid <= j){
ll cost = get_cost(mid,j);
if(cost > best){
best = cost;
opt_mid = j;
}
}
}
amax(ans,best);
go(l,mid-1,optl,opt_mid);
go(mid+1,r,opt_mid,optr);
}
void solve(int test_case)
{
cin >> n >> m;
rep(i,n) cin >> a[i].ss >> a[i].ff;
sort(a.begin(),a.begin()+n);
vector<int> b(n);
rep(i,n) oa[i] = b[i] = a[i].ss;
c = b;
sort(all(c));
c.resize(unique(all(c))-c.begin());
int siz = sz(c);
rep(i,n) b[i] = lower_bound(all(c),b[i])-c.begin();
rep(i,n) a[i].ss = b[i];
wt.build(b,n);
go(0,n-1,0,n-1);
cout << ans << endl;
}
int main()
{
fastio;
int t = 1;
// cin >> t;
rep1(i, t) {
solve(i);
}
return 0;
}
