#include <iostream>
// #include <fstream>
// std::ifstream cin ("tttt.in");
// std::ofstream cout ("tttt.out");
#include <cmath>
#include <set>
#include <map>
#include <queue>
#include <string>
#include <vector>
#include <array>
#include <algorithm>
#include <numeric>
#include <iomanip>
#include <unordered_set>
#include <stack>
#include <ext/pb_ds/assoc_container.hpp>
#include <random>
#include <chrono>
#include <bitset>
#include <complex>
using namespace std;
using namespace __gnu_pbds;
#define ll long long
#define f first
#define s second
template <class T> using iset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template <typename T, typename U>
bool emin(T &a, const U &b) { return b < a ? a = b, true : false; }
template <typename T, typename U>
bool emax(T &a, const U &b) { return b > a ? a = b, true : false; }
typedef uint64_t hash_t;
ll const inf = (ll) 1e15 + 7;
int const M = (ll) 1e9 + 7;
int const IM = (ll) 5e8 + 4;
struct wave {
int n;
vector<vector<ll>> a, pre;
vector<ll> v;
void init(vector<ll> b) {
map<ll, int> c; n = 0;
for(auto &u : b) c[u] = 0;
v = vector<ll>(c.size());
for(auto &u : c) v[u.s = n++] = u.f;
for(auto &u : b) u = c[u];
a = pre = vector<vector<ll>>(n * 4, {0});
build(b);
}
void build(vector<ll> b, int x, int l, int r) {
for(auto &u : b) pre[x].push_back(pre[x].back() + v[u]);
if(l == r) return;
int m = (l + r) / 2;
vector<ll> nex[2];
for(auto &u : b) a[x].push_back(a[x].back() + (u <= m));
for(auto &u : b) nex[u > m].push_back(u);
build(nex[0], x * 2, l, m);
build(nex[1], x * 2 + 1, m + 1, r);
}
ll get(int rl, int rr, int c, int x, int l, int r) {
if(l == r) return c * v[l];
int m = (l + r) / 2, nl = a[x][rl - 1], nr = a[x][rr];
if(nr - nl >= c) return get(nl + 1, nr, c, x * 2, l, m);
return pre[x * 2][nr] - pre[x * 2][nl] + get(rl - nl, rr - nr, c - nr + nl, x * 2 + 1, m + 1, r);
}
ll get(int rl, int rr, int c) { return get(rl + 1, rr + 1, c, 1, 0, n); }
void build(vector<ll> b) { build(b, 1, 0, n); }
} w;
int n, k;
vector<pair<ll, ll>> a;
ll an = -inf;
void go(int rl = 0, int rr = n - 1, int l = 0, int r = n - k) {
if(l > r) return;
int m = (l + r) / 2;
pair<ll, int> bes = {-inf, -1};
for(int i = max(rl, m + k - 1); i <= rr; i++)
emax(bes, make_pair(-w.get(m, i, k) - 2 * (a[i].s - a[m].s), i));
emax(an, bes.f);
go(rl, (bes.s != -1 ? bes.s : rr), l, m - 1); go((bes.f != -1 ? : bes.f), rr, m + 1, r);
}
int main() {
cin >> n >> k;
a = vector<pair<ll, ll>>(n); for(auto &u : a) cin >> u.f >> u.s;
sort(a.begin(), a.end(), [](auto x, auto y){ return x.s < y.s; });
vector<ll> b(n); for(int i = 0; i < n; i++) b[i] = -a[i].f;
w.init(b);
go();
cout << an;
}
