#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define eb emplace_back
#define pb push_back
#define fi first
#define se second
#define ii pair<int,int>
#define ve vector
#define all(x) x.begin(), x.end()
#define fo(i,a,b) for (int i=(a); i<=(b); ++i)
#define fd(i,a,b) for (int i=(a); i>=(b); --i)
#define maxi(a, b) a = max(a, b)
#define mini(a, b) a = min(a, b)
#define siz(x) ((int)(x).size())
#define vi ve<int>
#define _ << ' ' <<
const int N = 5e5+5, inf = 1e9+10, mod = 1e9+7;
bool MBE;
/**
**/
struct BIT {
ll f[N];
void upd(int x, ll v) {
for (; x; x-=x&-x) {
f[x] += v;
}
}
ll get(int x) {
ll res = 0;
for (; x<N; x+=x&-x) {
res += f[x];
}
return res;
}
int topk(int k) {
int l=1, r=2e5, mid, res=-1;
while (l <= r) {
mid=(l+r)/2;
if (get(mid)>=k) res=mid, l=mid+1;
else r=mid-1;
}
return res;
}
} cnt, sum;
int n, m, cl=1, cr=0;
ii a[N];
vi z;
ll ans=0;
void upd(int p, int v) {
cnt.upd(a[p].fi,v);
sum.upd(a[p].fi,v*z[a[p].fi-1]);
}
ll cost(int l, int r) {
int nx=min(r-l+1,m);
while (cl<l) upd(cl++,-1);
while (cr>r) upd(cr--,-1);
while (cl>l) upd(--cl,1);
while (cr<r) upd(++cr,1);
int pos=cnt.topk(nx), tim=nx-cnt.get(pos+1);
return sum.get(pos+1)+1LL*tim*z[pos-1]-2LL*(a[r].se-a[l].se);
}
void dnc(int l, int r, int optl, int optr) {
if (l>r) return;
int mid=(l+r)/2;
pair<ll,int> best={-1e18,-1};
fo(i,optl,min(mid-m+1,optr)) {
best=max(best,pair<ll,int>{cost(i,mid),i});
}
maxi(ans,best.fi);
if (best.se==-1) best.se=optl;
dnc(l,mid-1,optl,best.se);
dnc(mid+1,r,best.se,optr);
}
void sol() {
cin >> n >> m;
fo(i,1,n) {
cin >> a[i].fi >> a[i].se;
z.pb(a[i].fi);
}
sort(all(z)); z.resize(unique(all(z))-z.begin());
sort(a+1, a+n+1, [&](ii x, ii y)->bool{
if (x.se==y.se) return 0;
return x.se<y.se;
});
fo(i,1,n) {
a[i].fi=lower_bound(all(z),a[i].fi)-z.begin()+1;
}
dnc(1,n,1,n);
cout << ans;
}
bool MED;
signed main(){
ios::sync_with_stdio(0); cin.tie(0);
if(fopen("A.inp","r")) {
freopen("A.inp","r",stdin);
freopen("A.out","w",stdout);
}
int tc = 1; // cin >> tc;
fo(i,1,tc) sol();
// cerr << "Memory = " << abs(&MED - &MBE)/1024.0/1024.0 << " MB";
return 0;
}
