#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double dou;
#define pii pair<int, int>
#define fi first
#define se second
#define pb push_back
#define ALL(v) v.begin(), v.end()
#define BITj(x, j) (((x)>>(j))&1)
#define MASK(x) (1LL<<(x))
template<typename T> bool maximize(T &x, const T &y) {
if (x < y) {x = y; return 1;}
return 0;
}
template<typename T> bool minimize(T &x, const T &y) {
if (x > y) {x = y; return 1;}
return 0;
}
const int maxn = 2e5+5;
int n, m;
pii a[maxn];
ll ans = LLONG_MIN;
void input() {
cin >> n >> m;
for (int i = 1; i <= n; i++) {
cin >> a[i].se >> a[i].fi;
}
}
namespace sub3{
struct SMT{
int trsz;
vector<ll> tr;
vector<int> cnt;
void init(int n) {
trsz = 1;
while (trsz < n) trsz <<= 1;
tr.assign(trsz<<1, 0);
cnt.assign(trsz<<1, 0);
}
void update(int k, int x, int c) {
k += trsz-1;
while (k > 0) {
tr[k] += x*c;
cnt[k] += c;
k >>= 1;
}
}
ll walk(int id, int &target) {
if (target >= cnt[id]) {
target -= cnt[id];
return tr[id];
}
if (id >= trsz) {
return 0;
}
ll sum = walk(id<<1|1, target);
if (target > 0) {
sum += walk(id<<1, target);
}
return sum;
}
ll query() {
int temp = m;
return walk(1, temp);
}
};
vector<int> values;
SMT tr;
void discretize() {
sort(ALL(values));
values.erase(unique(ALL(values)), values.end());
}
int fval(int x) {
return lower_bound(ALL(values), x)-values.begin()+1;
}
void insval(int x) {
int cor = fval(x);
tr.update(cor, x, 1);
}
void remval(int x) {
int cor = fval(x);
tr.update(cor, x, -1);
}
void dnc(int l, int r, int opl, int opr) {
//find best, minimize ans
// cout << "begin " << l << ' ' << r << "\n";
int opt = -1, mid = (l+r)>>1;
ll best = LLONG_MIN;
for (int i = max(mid, opl); i <= opr; i++) {
insval(a[i].se);
ll val = tr.query() - 2LL*(a[i].fi-a[mid].fi);
if (mid+m-1 <= i && maximize(best, val)) {
opt = i;
}
}
maximize(ans, best);
//clear & continue
int nxtmid;
if (l < mid) {
nxtmid = (l+mid-1)>>1;
for (int i = max(mid, opl); i <= opr; i++) {
remval(a[i].se);
}
for (int i = nxtmid; i < min(opl, mid); i++) {
insval(a[i].se);
}
dnc(l, mid-1, opl, opt);
for (int i = max(mid, opl); i <= opr; i++) {
insval(a[i].se);
}
for (int i = nxtmid; i < min(opl, mid); i++) {
remval(a[i].se);
}
}
if (mid < r) {
nxtmid = (r+mid+1)>>1;
for (int i = mid; i < nxtmid; i++) {
remval(a[i].se);
}
for (int i = max(nxtmid, opt); i <= opr; i++) {
remval(a[i].se);
}
dnc(mid+1, r, opt, opr);
for (int i = mid; i < nxtmid; i++) {
insval(a[i].se);
}
for (int i = max(nxtmid, opt); i <= opr; i++) {
insval(a[i].se);
}
}
//clear & return
for (int i = max(mid, opl); i <= opr; i++) {
remval(a[i].se);
}
// cout << "end " << l << ' ' << r << "\n";
}
void solve() {
sort(a+1, a+n+1);
for (int i= 1; i <= n; i++) {
values.pb(a[i].se);
}
discretize();
tr.init((int)values.size());
dnc(1, n-m+1, 1, n);
cout << ans;
}
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
#define name "task"
if (fopen(name".inp", "r")) {
freopen(name".inp", "r", stdin);
freopen(name".out", "w", stdout);
}
input();
return sub3::solve(), 0;
}
/*
5 3
2 1
4 2
6 4
8 8
10 16
multiset<int> st1, st2;
ll cursum = 0;
void insval(int x) {
// cout << "insval " << x << "\n";
st1.insert(x);
cursum += x;
while ((int)st1.size() > m) {
int val = *st1.begin();
st1.erase(st1.begin());
cursum -= val;
st2.insert(val);
}
}
void remval(int x) {
// cout << "remval " << x << "\n";
auto it = st1.find(x);
if (it == st1.end()) st2.erase(st2.find(x));
else {
st1.erase(it);
cursum -= x;
}
if (!st2.empty() && (int)st1.size() < m) {
it = prev(st2.end());
int val = *it;
st2.erase(it);
st1.insert(val);
cursum += val;
}
}
*/
