#include <iostream>
#include <array>
#include <map>
#include <queue>
#include <vector>
#include <algorithm>
#define ll long long
using namespace std;
ll n, m, f, mx, s, cnt, cl, cr;
map <ll, ll> mp;
vector <ll> V;
array<ll, 2> A[200000];
queue <array<ll, 4>> Q[2];
struct SegTree{
ll st[800000], tot[800000];
void update(ll id, ll l, ll r, ll q) {
if (l == r) {
st[id] ^= V[l], tot[id] ^= 1;
return;
}
ll mid = (l+r)/2;
if (q <= mid) update(id*2, l, mid, q);
else update(id*2+1, mid+1, r, q);
st[id] = st[id*2] + st[id*2+1];
tot[id] = tot[id*2] + tot[id*2+1];
}
ll query(ll id, ll l, ll r, ll z) {
if (l == r) {
z -= tot[id];
if (z == 0) return st[id];
else return -1e18;
}
ll mid = (l+r)/2;
if (tot[id*2+1] >= z) return query(id*2+1, mid+1, r, z);
else return st[id*2+1] + query(id*2, l, mid, z-tot[id*2+1]);
}
}ST;
void solve(ll l, ll r, ll ql, ll qr) {
ll mid = (l+r)/2;
while (cr+1 < max(mid, ql)) {
++cr;
ST.update(1, 0, n-1, A[cr][0]);
}
while (cl < mid) {
ST.update(1, 0, n-1, A[cl][0]);
++cl;
}
ll opt = -1, optid = max(mid, ql), res;
//cout << cl << " " << cr << "*" << mid << " " << ql << " " << ST.st[1] << endl;
for (int i=max(mid, ql); i<=qr; ++i) {
ST.update(1, 0, n-1, A[i][0]);
res = ST.query(1, 0, n-1, m) - 2*A[i][1] + 2*A[mid][1];
if (opt <= res) {
opt = res;
optid = i;
}
}
for (int i=max(mid, ql); i<=qr; ++i) {
ST.update(1, 0, n-1, A[i][0]);
}
f = max(f, opt);
if (l < mid) Q[1].push({l, mid-1, ql, optid});
if (mid < r) Q[1].push({mid+1, r, optid, qr});
}
void bfs() {
while (!Q[0].empty()) {
cl = 0, cr = -1;
while (!Q[0].empty()) {
auto [l, r, ql, qr] = Q[0].front();
Q[0].pop();
solve(l, r, ql, qr);
}
swap(Q[0], Q[1]);
while (cr+1 < n) {
++cr;
ST.update(1, 0, n-1, A[cr][0]);
}
while (cl < n) {
ST.update(1, 0, n-1, A[cl][0]);
++cl;
}
}
}
int main() {
cin >> n >> m;
for (int i=0; i<2; ++i) {
while (!Q[i].empty()) Q[i].pop();
}
V.clear();
f = -1e18;
for (int i=0; i<n; ++i) {
cin >> A[i][0] >> A[i][1];
++mp[A[i][0]];
}
for (auto &[x, y] : mp) {
auto tmp = y;
for (int i=0; i<y; ++i) V.push_back(x);
y = cnt;
cnt += tmp;
}
sort(A, A+n, [](auto a, auto b) {
return a[1] < b[1];
});
for (int i=0; i<n; ++i) {
A[i][0] = mp[A[i][0]]++;
}
Q[0].push({0, n-m, m-1, n-1});
bfs();
cout << f << '\n';
}
