#include <bits/stdc++.h>
#define ii pair<int, int>
#define fi first
#define se second
#define inf 0x3f3f3f3f3f3f3f3f
using namespace std;
using ll = long long;
const ll mod=1e9+7;
const int nx=2e5+5;
const int base=1e9;
bool cmp(ii a, ii b)
{
return a.se<b.se;
}
struct PST
{
struct dak
{
ll sum=0;
int cnt=0, l=0, r=0;
};
int cur=1;
vector<dak> nod;
void add()
{
nod.emplace_back();
}
dak join(int l, int r)
{
return dak{nod[l].sum+nod[r].sum, nod[l].cnt+nod[r].cnt, l, r};
}
int update(int id, int l, int r, int p)
{
if(l==r)
{
add();
nod[cur]=nod[id];
nod[cur].sum+=p;
nod[cur].cnt++;
return cur++;
}
int mid=(l+r)>>1;
add();
if(p<=mid) nod[cur]=join(update(nod[id].l, l, mid, p), nod[id].r);
else nod[cur]=join(nod[id].l, update(nod[id].r, mid+1, r, p));
return cur++;
}
ll find(int idl, int idr, int l, int r, int k)
{
if(l==r) return 1ll*min(k, nod[idr].cnt-nod[idl].cnt)*l;
int mid=(l+r)>>1;
int le=nod[idl].r, ri=nod[idr].r;
if(nod[ri].cnt-nod[le].cnt>=k) return find(le, ri, mid+1, r, k);
return nod[ri].sum-nod[le].sum+find(nod[idl].l, nod[idr].l, l, mid, k-nod[ri].cnt+nod[le].cnt);
}
} st;
int n, k, root[nx];
ii a[nx];
ll res=-inf;
ll cost(int l, int r)
{
if(l<0 || r>n) return -inf;
if(r-l+1<k) return -inf;
return st.find(root[l-1], root[r], 1, base, k)-2ll*(a[r].se-a[l].se);
}
void solve(int l, int r, int optl, int optr)
{
if(l>r) return;
int mid=(l+r)>>1;
int pos=0;
ll cur=-inf-1;
for(int i = optl; i <= min(mid, optr); i++)
if(cost(i, mid)>cur)
cur=cost(i, mid), pos=i;
res=max(res, cur);
solve(l, mid-1, optl, pos);
solve(mid+1, r, pos, optr);
}
int main()
{
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
st.add();
st.add();
cin>>n>>k;
for(int i = 1; i <= n; i++)
cin>>a[i].fi>>a[i].se;
sort(a+1, a+n+1, cmp);
root[0]=1;
for(int i = 1; i <= n; i++)
root[i]=st.update(root[i-1], 1, base, a[i].fi);
solve(1, n, 1, n);
cout<<res;
}
