#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/rope>
using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;
random_device(rd);
mt19937 rng(rd());
const long long FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
struct custom_hash
{
template<class T>
unsigned long long operator()(T v) const
{
unsigned long long x = v;
x += FIXED_RANDOM;
// x += 11400714819323198485ull;
// x = (x ^ (x >> 30)) * 13787848793156543929ull;
x = (x ^ (x >> 27)) * 10723151780598845931ull;
return x ^ (x >> 31);
}
};
template<class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<class T, class U> using hash_table = gp_hash_table<T, U, custom_hash>;
template<class T>
T randomize(T mod)
{
return (uniform_int_distribution<T>(0, mod - 1))(rng);
}
template<class T>
void readi(T &x)
{
x = 0;
bool negative = false;
char c = ' ';
while (c < '-')
{
c = getchar();
}
if (c == '-')
{
negative = true;
c = getchar();
}
while (c >= '0')
{
x = x * 10 + (c - '0');
c = getchar();
}
if (negative)
{
x = -x;
}
}
template<class T>
void printi(T output)
{
if (output == 0)
{
putchar('0');
return;
}
if (output < 0)
{
putchar('-');
output = -output;
}
int buf[20], n = 0;
while(output)
{
buf[n] = ((output % 10));
output /= 10;
n++;
}
for (n--; n >= 0; n--)
{
putchar(buf[n] + '0');
}
return;
}
template<class T>
void ckmin(T &a, T b)
{
a = min(a, b);
}
template<class T>
void ckmax(T &a, T b)
{
a = max(a, b);
}
long long expo(long long a, long long e, long long mod)
{
return ((e == 0) ? 1 : ((expo(a * a % mod, e >> 1, mod)) * ((e & 1) ? a : 1) % mod));
}
template<class T, class U>
void nmod(T &x, U mod)
{
if (x >= mod) x -= mod;
}
template<class T>
T gcd(T a, T b)
{
return (b ? gcd(b, a % b) : a);
}
#define y0 ___y0
#define y1 ___y1
#define MP make_pair
#define PB push_back
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define DBG(x) cerr << #x << " = " << (x) << endl
#define SZ(x) ((int) ((x).size()))
#define FOR(i, a, b) for (auto i = (a); i < (b); i++)
#define FORD(i, a, b) for (auto i = (a) - 1; i >= (b); i--)
#define ALL(x) (x).begin(), (x).end()
const long double PI = 4.0 * atan(1.0);
const long double EPS = 1e-9;
#define MAGIC 347
#define SINF 10007
#define CO 1000007
#define INF 1000000007
#define BIG 1000000931
#define LARGE 1696969696967ll
#define GIANT 2564008813937411ll
#define LLINF 2696969696969696969ll
#define MAXN 200013
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<ld, ld> pdd;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<ld> vd;
typedef vector<pii> vpi;
typedef vector<pll> vpl;
typedef vector<pdd> vpd;
int N, M;
pll arr[MAXN];
ll ans = -LLINF;
ll sum = 0;
ordered_set<pll> ord;
multiset<ll> negative;
pii stor;
void ins(ll x)
{
//if this will become among the top k, subtract kth and add this
if (negative.find(x) != negative.end())
{
negative.erase(negative.find(x));
return;
}
auto p = *ord.find_by_order(SZ(ord) - (M - 2));
if (p.fi <= x)
{
sum -= p.fi;
sum += x;
}
ord.insert({x, randomize(LLINF)});
}
void del(ll x)
{
//if this is currently among the top k, subtract this and add the kth
auto pp = ord.UB({x, -LLINF});
if (pp -> fi != x)
{
negative.insert(x);
return;
}
ord.erase(pp);
auto p = *ord.find_by_order(SZ(ord) - (M - 2));
if (p.fi <= x)
{
sum -= x;
sum += p.fi;
}
}
void move(pii p)
{
while(stor.se < p.se)
{
stor.se++;
ins(arr[stor.se - 1].se);
}
while(stor.se > p.se)
{
del(arr[stor.se - 1].se);
stor.se--;
}
while(stor.fi < p.fi)
{
del(arr[stor.fi - 1].se);
stor.fi++;
}
while(stor.fi > p.fi)
{
stor.fi--;
ins(arr[stor.fi - 1].se);
}
}
void solve(int L, int R, int optl, int optr)
{
//it must start off containing L + 1..optl - 1
if (L > R) return;
int mid = (L + R) >> 1;
ll best = -LLINF; int opt = -1;
FOR(i, optl, optr + 1)
{
// cerr << "INS " << i - 1 << endl;
move({mid + 2, i});
if (i - mid + 1 >= M)
{
ll cur = arr[mid].se + 2 * arr[mid].fi + arr[i].se - 2 * arr[i].fi + sum;
if (cur > best)
{
best = cur;
opt = i;
}
}
}
ckmax(ans, best);
solve(L, mid - 1, optl, opt);
solve(mid + 1, R, opt, optr);
//it must end off containing R...whatever
}
int32_t main()
{
ios_base::sync_with_stdio(0); cin.tie(0);
// cout << fixed << setprecision(10);
// cerr << fixed << setprecision(10);
// if (fopen("file.in", "r"))
// {
// freopen ("file.in", "r", stdin);
// freopen ("file.out", "w", stdout);
// }
cin >> N >> M;
FOR(i, 0, N)
{
cin >> arr[i].se >> arr[i].fi;
}
sort(arr, arr + N);
// FOR(i, 0, N)
// {
// cerr << arr[i].fi << ' ' << arr[i].se << endl;
// }
FOR(i, 0, M)
{
ord.insert({-LARGE, randomize(LLINF)});
}
sum = (-LARGE) * (M - 2);
stor = {2, 1};
solve(0, N - M, M - 1, N - 1);
cout << ans << '\n';
// cerr << "time elapsed = " << (clock() / (CLOCKS_PER_SEC / 1000)) << " ms" << endl;
return 0;
}
/* READ READ READ
* int overflow, maxn too small, special cases (n=1?, two distinct?), cin.tie() interactive
* reread the problem, try small cases
* note down possible sources of error as you go
* do smth instead of nothing
*/
