#include<bits/stdc++.h>
#pragma GCC optimize("unroll-loops,no-stack-protector")
using namespace std;
typedef int ll;
typedef long double ld;
typedef pair<ll,ll> pll;
const ll MOD=1e9+7;
const ll MOD2=998244353;
const ll N=4e5+5;
const ld pi=3.14159265359;
const ll INF=(1LL<<32);
#define SQ(i) ((i)*(i))
#define REP(i,n) for(ll i=0;i<n;i++)
#define REP1(i,n) for(ll i=1;i<=n;i++)
#define pb push_back
#define mp make_pair
#define X first
#define Y second
#define setp setprecision
#define lwb lower_bound
#define SZ(_a) (ll)_a.size()
struct node{
ll l,r,cnt;long long sum;
node *lc,*rc;
}*rt=new node{0,(1LL<<30),0,0,0,0};
ll pl=1,pr=0,n,m,x,y;
long long ans=-INF;
vector<pll> v;
ll get_cnt(node *nd){
if(!nd)return 0;
return nd->cnt;
}
long long get_sum(node *nd){
if(!nd)return 0;
return nd->sum;
}
void insert(node *nd,ll to,ll d){
if(nd->l==nd->r-1){nd->cnt+=d;nd->sum=nd->l*nd->cnt;return ;}
ll mid=(nd->l+nd->r)/2;
if(to<mid){
if(!nd->lc)nd->lc=new node{nd->l,mid,0,0,0,0};
insert(nd->lc,to,d);
}else{
if(!nd->rc)nd->rc=new node{mid,nd->r,0,0,0,0};
insert(nd->rc,to,d);
}
nd->cnt=get_cnt(nd->lc)+get_cnt(nd->rc);
nd->sum=get_sum(nd->lc)+get_sum(nd->rc);
}
long long query(node *nd,ll le){
if(nd->l==nd->r-1){return le*nd->l;}
ll mid=(nd->l+nd->r)/2;
if(le>=get_cnt(nd->rc)){
if(!nd->lc)nd->lc=new node{nd->l,mid,0,0,0,0};
return get_sum(nd->rc)+query(nd->lc,le-get_cnt(nd->rc));
}else{
if(!nd->rc)nd->rc=new node{mid,nd->r,0,0,0,0};
return query(nd->rc,le);
}
}
long long get_ans(ll l,ll r){
++l;--r;
while(pl>l){insert(rt,v[--pl].X,1);}
while(pr<r){insert(rt,v[++pr].X,1);}
while(pl<l){insert(rt,v[pl++].X,-1);}
while(pr>r){insert(rt,v[pr--].X,-1);}
if(get_cnt(rt)<m)return -INF;
return query(rt,m);
}
void solve(ll ql,ll qr,ll al,ll ar){
if(ql>qr)return ;
ll mid=(ql+qr)/2;
long long bans=-INF,bpos=al;
for(int i=min(mid-1,ar);i>=al;i--){
long long current = get_ans(i,mid);
long long tans=(get_cnt(rt)<m?-INF:current-2*(v[mid].Y-v[i].Y)+v[mid].X+v[i].X);
if(tans>bans){
bpos=i,bans=tans;
}
ans=max(ans,tans);
}
solve(ql,mid-1,al,bpos);
solve(mid+1,qr,bpos,ar);
}
int main(){
ios_base::sync_with_stdio(0);cin.tie(0);
cin>>n>>m;
m-=2;
REP(i,n)cin>>x>>y,v.pb(mp(x,y));
sort(v.begin(),v.end(),[](pll a,pll b){
return (a.Y!=b.Y?a.Y<b.Y:a.X>b.X);
});
solve(0,n-1,0,n-1);
cout<<ans<<"\n";
return 0;
}
