/*
https://oj.uz/problem/view/JOI19_cake3
Cake 3
*/
#include <bits/stdc++.h>
using namespace std;
#define N 200000
namespace kactl {
typedef long long ll;
#define sz(x) int(x.size())
/**
* Author: Lukas Polacek
* Date: 2009-10-30
* License: CC0
* Source: folklore/TopCoder
* Description: Computes partial sums a[0] + a[1] + ... + a[pos - 1], and updates single elements a[i],
* taking the difference between the old and new value.
* Time: Both operations are $O(\log N)$.
* Status: Stress-tested
*/
struct FT {
vector<ll> s;
vector<int> k;
void init(int n) {
s.assign(n, 0);
k.assign(n, 0);
}
void update(int pos, ll dif, int c) { // a[pos] += dif
// printf("upd[%d] {%lld, %d}\n", pos, dif, c);
for (; pos < sz(s); pos |= pos + 1) {
s[pos] += dif;
k[pos] += c;
}
}
ll query(int pos) { // sum of values in [0, pos)
ll res = 0;
for (; pos > 0; pos &= pos - 1) res += s[pos - 1];
return res;
}
int lower_bound(int c) {// min pos st sum of [0, pos] >= sum
// Returns n if no sum is >= sum, or -1 if empty sum is.
if (c <= 0) return -1;
int pos = 0; //ll sum = 0;
for (int pw = 1 << 25; pw; pw >>= 1) {
if (pos + pw <= sz(k) && k[pos + pw - 1] < c) {
pos += pw, c -= k[pos - 1];
// sum += s[pos-1];
}
}
return pos;
}
ll q_(int c) {
return query(lower_bound(c) + 1);
}
} ft;
}
array<int, 2> aa[N];
int ii[N];
int l_ = 0, r_ = -1, m_;
long long query(int l, int r) {
if (r - l + 1 < m_)
return -0x3f3f3f3f3f3f3f3f;
// printf("QUERY [%d, %d]\n", l, r);
while (l_ < l)
kactl::ft.update(ii[l_], -aa[l_][1], -1), l_++;
while (l_ > l)
l_--, kactl::ft.update(ii[l_], +aa[l_][1], +1);
while (r_ > r)
kactl::ft.update(ii[r_], -aa[r_][1], -1), r_--;
while (r_ < r)
r_++, kactl::ft.update(ii[r_], +aa[r_][1], +1);
// printf("%d | ", kactl::ft.lower_bound(m_));
return kactl::ft.q_(m_) - (long long) 2 * (aa[r][0] - aa[l][0]);
}
long long ans = -0x3f3f3f3f3f3f3f3f;
void dnc(int lo, int ro, int l, int r) {
long long tmp;
int m, mo;
if (l > r)
return;
m = (l + r) / 2, mo = lo;
tmp = query(mo, m);
// tmp = -0x3f3f3f3f3f3f3f3f;
for (int i = lo; i <= ro; i++) {
long long tmp_ = query(i, m);
if (tmp_ > tmp) {
tmp = tmp_;
mo = i;
}
}
ans = max(ans, tmp);
if (mo == -1) {
assert(0);
dnc(lo, ro, m + 1, r);
} else {
dnc(lo, mo, l, m - 1);
dnc(mo, ro, m + 1, r);
}
}
int main() {
static int ii_[N];
int n;
scanf("%d%d", &n, &m_);
for (int i = 0; i < n; i++) {
scanf("%d%d", &aa[i][1], &aa[i][0]);
ii_[i] = i;
}
sort(aa, aa + n);
sort(ii_, ii_ + n, [&](int i, int j) {
return aa[i][1] > aa[j][1];
});
for (int i = 0; i < n; i++)
ii[ii_[i]] = i;
kactl::ft.init(n + 69);
// for (int i = 0; i < n; i++)
// printf("ii[%d]? = %d\n", i, ii[i]);
// for (int i = 0; i < n; i++)
// for (int j = i; j < n; j++)
// ans = max(ans, query(i, j));
// printf("q(%d, %d) = %lld\n", 0, 2, query(0, 2));
dnc(0, n - 1, 0, n - 1);
printf("%lld\n", ans);
return 0;
}
