//Challenge: Accepted
#include <iostream>
#include <algorithm>
#include <vector>
#include <utility>
#include <queue>
#define ll long long
#define maxn 200005
#define pii pair<ll, ll>
#define ff first
#define ss second
#define io ios_base::sync_with_stdio(0);cin.tie(0);
using namespace std;
int n, m;
pii a[maxn];
inline bool cmp(pii a, pii b) {
return a.ss < b.ss;
}
inline void ins(int l, int r, priority_queue<ll, vector<ll>, greater<ll> > & pq, ll & sum) {
for (int i = l;i < r;i++) {
sum += a[i].ff;
pq.push(a[i].ff);
if (pq.size() > m) {
sum -= pq.top();
pq.pop();
}
}
}
ll ans = -(1LL<<60);
void solve(int l, int r, int ql, int qr) {
if (r <= l || qr <= ql) return;
if (qr - ql == 1) {
priority_queue<ll, vector<ll>, greater<ll> > pq;
ll sum = 0;
ins(ql, l, pq, sum);
for (int i = l;i < r;i++) {
ins(i, i + 1, pq, sum);
//cout << i << " " << ql << " " << sum - 2 * (a[i].ss - a[ql].ss) << 0 << endl;
ans = max(ans, sum - 2 * (a[i].ss - a[ql].ss));
}
return;
}
int mid = (l + r) / 2;
ll best = -(1LL<<60), bind = 0;
ll sum = 0;
priority_queue<ll, vector<ll>, greater<ll> > pq;
ins(min(qr, mid - m + 2), mid + 1, pq, sum);
//cout << sum << endl;
for (int i = min(qr - 1, mid - m + 1);i >= ql;i--) {
ins(i, i + 1, pq, sum);
ll val = sum - 2 * (a[mid].ss - a[i].ss);
if (val > best) {
best = val;
bind = i;
}
}
//cout << mid << " " << bind << " " << best << " " << 1 << endl;
ans = max(ans, best);
solve(l, mid, ql, bind + 1);
solve(mid + 1, r, bind, qr);
}
int main() {
io
cin >> n >> m;
for (int i = 0;i < n;i++) cin >> a[i].ff >> a[i].ss;
sort(a, a + n, cmp);
solve(m - 1, n, 0, n);
cout << ans << "\n";
}
/*
5 3
2 1
4 2
6 4
8 8
10 16
8 4
112103441 501365808
659752417 137957977
86280801 257419447
902409188 565237611
965602301 689654312
104535476 646977261
945132881 114821749
198700181 915994879
*/
