#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;
typedef tree<long long, null_type, less_equal<>,
rb_tree_tag, tree_order_statistics_node_update>
ordered_set;
#define ll long long
#define ii pair<ll,ll>
#ifndef DEBUG
#define cerr if (0) cerr
#define endl '\n'
#endif
const ll inf=1e15;
const ll maxn=2e5+5;
const ll mod=1e9+7;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
ll n,k;
ll dp[maxn],cnt[maxn],fen[maxn],arr[maxn];
pair<ii,ll> ord[maxn];
ll inv[maxn];
ll h[maxn];
ll lptr,rptr;
multiset<ll> s;
void upd(ll *arr, ll x, ll v){
while (x<maxn){
arr[x]+=v;
x+=(x&-x);
}
}
ll query(ll *arr, ll x){
ll ans=0;
while (x){
ans+=arr[x];
x-=(x&-x);
}
return ans;
}
ll query(ll *arr, ll x, ll y){
return query(arr,y)-query(arr,x-1);
}
void add(ll x){
upd(cnt,inv[x],1);
upd(fen,inv[x],arr[x]);
s.insert(h[x]);
}
void sub(ll x){
upd(cnt,inv[x],-1);
upd(fen,inv[x],-arr[x]);
s.erase(s.find(h[x]));
}
ll qry(ll l, ll r){
while (lptr>l) add(--lptr);
while (lptr<l) sub(lptr++);
while (rptr>r) sub(rptr--);
while (rptr<r) add(++rptr);
ll le=0,ri=n,m;
while (le!=ri-1){
m=(le+ri)>>1;
if (query(cnt,m,n)>k) le=m;
else ri=m;
}
if (query(cnt,ri,n)!=k) return 0;
return query(fen,ri,n)-2*((*--s.end())-*s.begin());
}
void dnc(ll l, ll r, ll optl, ll optr){
if (l>r) return;
ll m=(l+r)>>1,opt=optl,res=0;
for (int i=optl;i<=min(m,optr);i++){
res=qry(i,m);
if (res>dp[m]) dp[m]=res,opt=i;
}
dnc(l,m-1,optl,opt);
dnc(m+1,r,opt,optr);
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cin>>n>>k;
for (int i=1;i<=n;i++){
cin>>ord[i].first.second>>ord[i].first.first;
}
sort(ord+1,ord+1+n);
for (int i=1;i<=n;i++){
h[i]=ord[i].first.first;
arr[i]=ord[i].first.second;
ord[i].second=i;
swap(ord[i].first.first,ord[i].first.second);
}
sort(ord+1,ord+1+n);
for (int i=1;i<=n;i++){
inv[ord[i].second]=i;
}
lptr=1,rptr=1;
add(1);
dnc(1,n,1,n);
cout<<*max_element(dp+1,dp+n+1);
return 0;
}
