#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define ordered_set <int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>
#define ordered_multiset <int, null_type, less_equal <int>, rb_tree_tag, tree_order_statistics_node_update>
#define int long long
#define double long double
#define pii pair <int, int>
#define tiii tuple <int, int, int>
#define tiiii tuple <int, int, int, int>
#define emb emplace_back
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define iShowSpeed cin.tie(NULL)->sync_with_stdio(false)
#define matrix vector <vector <int>>
#define mat(n, m) vector <vector <int>> (n, vector <int> (m));
const int mod = 1e9 + 7;
const int inf = 1e18;
const matrix II = {{1, 0}, {0, 1}};
const int N = 2e5 + 5;
int n, m, ans = -inf, id;
tiii a[N];
unordered_map <int, int> com, moc;
struct persistent {
struct node {
int sum, cnt;
node *l, *r;
node() : sum(0), cnt(0), l(0), r(0) {}
};
typedef node* pnode;
pnode root[N];
void build(int l, int r, pnode &i){
i = new node();
if (l == r) return;
int mid = (l + r) / 2;
build(l, mid, i->l), build(mid + 1, r, i->r);
}
void update(int l, int r, pnode &i, pnode j, int idx, int val){
i = new node(*j);
if (l == r) return i->sum = val, i->cnt = 1, void();
int mid = (l + r) / 2;
if (idx <= mid) update(l, mid, i->l, j->l, idx, val);
else update(mid + 1, r, i->r, j->r, idx, val);
i->sum = i->l->sum + i->r->sum;
i->cnt = i->l->cnt + i->r->cnt;
}
int query(int l, int r, pnode i, pnode j, int k){
if (l == r) return i->sum - j->sum;
int mid = (l + r) / 2;
if (i->r->cnt - j->r->cnt >= k) return query(mid + 1, r, i->r, j->r, k);
else return i->r->sum - j->r->sum + query(l, mid, i->l, j->l, k - i->r->cnt);
}
int cal(int l, int r){
return query(1, n, root[r], root[l - 1], m) - 2 * (get <0> (a[r]) - get <0> (a[l]));
}
} seg;
void dac(int l, int r, int left, int right){
if (r < l) return;
int mid = (l + r) / 2;
int mx = -inf, idx = left;
for (int i = left; i <= min(right, mid - m + 1); i++) {
int c = seg.cal(i, mid);
if (c > mx) {
mx = c;
idx = i;
}
}
dac(l, mid - 1, left, idx);
dac(mid + 1, r, idx, right);
ans = max(ans, mx);
}
int32_t main(){
iShowSpeed;
cin >> n >> m;
vector <pii> temp;
for (int i = 1; i <= n; i++) {
auto &[c, v, idx] = a[i];
cin >> v >> c;
idx = i;
temp.emb(v, idx);
}
sort(all(temp));
sort(a + 1, a + 1 + n);
for (auto [v, idx] : temp) {
com[idx] = ++id;
}
seg.build(1, n, seg.root[0]);
for (int i = 1; i <= n; i++) {
auto [c, v, idx] = a[i];
seg.update(1, n, seg.root[i], seg.root[i - 1], com[idx], v);
}
dac(m, n, 1, n);
cout << ans;
}
