#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif
const int N = 2e5 + 5;
const long long inf = 1e18;
int n, m, sz;
int cnt[4 * N];
long long s[4 * N];
array<int, 2> a[N];
vector<int> comp;
void upd(int i, int x, int id = 1, int l = 1, int r = sz) {
if (l == r) {
s[id] += x;
cnt[id] += x > 0 ? 1 : -1;
return;
}
int md = (l + r) / 2;
if (i <= md) {
upd(i, x, id * 2, l, md);
} else {
upd(i, x, id * 2 + 1, md + 1, r);
}
s[id] = s[id * 2] + s[id * 2 + 1];
cnt[id] = cnt[id * 2] + cnt[id * 2 + 1];
}
long long qry(int k, int id = 1, int l = 1, int r = sz) {
if (l == r) {
long long value = s[id] / cnt[id];
return value * k;
}
int md = (l + r) / 2;
if (k > cnt[id * 2 + 1]) {
return qry(k - cnt[id * 2 + 1], id * 2, l, md) + s[id * 2 + 1];
}
return qry(k, id * 2 + 1, md + 1, r);
}
void add(int i, int x) {
upd(a[i][0], x * comp[a[i][0] - 1]);
}
int L = 1, R = 0;
void shift(int a, int b) {
while (R < b) {
add(++R, 1);
}
while (L > a) {
add(--L, 1);
}
while (R > b) {
add(R--, -1);
}
while (L < a) {
add(L++, -1);
}
}
long long res = -inf;
void dc(int l, int r, int tl, int tr) {
if (l > r) {
return;
}
int md = (l + r) / 2;
pair<long long, int> best = {-inf, -1};
for (int i = tl; i <= min(tr, md - m + 1); ++i) {
shift(i, md);
best = max(best, {qry(m) - (long long) 2 * (a[md][1] - a[i][1]), i});
}
res = max(res, best.first);
dc(l, md - 1, tl, best.second);
dc(md + 1, r, best.second, tr);
}
int main() {
ios::sync_with_stdio(false); cin.tie(nullptr);
cin >> n >> m;
for (int i = 1; i <= n; ++i) {
cin >> a[i][0] >> a[i][1];
comp.push_back(a[i][0]);
}
sort(a + 1, a + n + 1, [&](auto u, auto v) {
return u[1] < v[1];
});
sort(comp.begin(), comp.end());
comp.erase(unique(comp.begin(), comp.end()), comp.end());
sz = comp.size();
for (int i = 1; i <= n; ++i) {
a[i][0] = lower_bound(comp.begin(), comp.end(), a[i][0]) - comp.begin() + 1;
}
dc(m, n, 1, n - m + 1);
cout << res;
return 0;
}
