#include<bits/stdc++.h>
#define forin(i, a, b) for(int i = a; i <= b; ++i)
#define ll long long
using namespace std;
const int N = 2e5 + 10;
int n, m;
ll ans, inf = 2e18;
ll s[N];
struct it {
int cnt;
ll sum;
it* lf;
it* rt;
it() : cnt(), sum(), lf(), rt() { }
void up(int i, ll val, int f = 1, int l = n) {
if(f == l) {
cnt = 1;
sum = val;
return;
}
int mid = f + l >> 1;
if(i <= mid) {
lf = lf ? new it(*lf) : new it();
lf -> up(i, val, f, mid);
}
else {
rt = rt ? new it(*rt) : new it();
rt -> up(i, val, mid + 1, l);
}
sum = cnt = 0;
if(lf) sum += lf -> sum, cnt += lf -> cnt;
if(rt) sum += rt -> sum, cnt += rt -> cnt;
}
};
ll sum(it* id) {
return id ? id -> sum : 0;
}
int cnt(it* id) {
return id ? id -> cnt : 0;
}
ll get(it* id1, it* id2, int f = 1, int l = n, int k = m) {
if(f == l) return sum(id2) - sum(id1);
int mid = f + l >> 1;
int res = cnt(id2 -> rt) - cnt(id1 -> rt);
ll val = sum(id2 -> rt) - sum(id1 -> rt);
if(res < k) {
if(!id1 -> lf) id1 -> lf = new it();
if(!id2 -> lf) id2 -> lf = new it();
return val + get(id1 -> lf, id2 -> lf, f, mid, k - res);
}
else {
if(!id1 -> rt) id1 -> rt = new it();
if(!id2 -> rt) id2 -> rt = new it();
return get(id1 -> rt, id2 -> rt, mid + 1, l, k);
}
}
struct piece {
ll v, c;
int i;
};
piece p[N];
vector<it*> tr;
void solve(int from = 1, int to = n, int f = 1, int l = n) {
if(f > l) return;
int mid = f + l >> 1, nxt = 0;
ll &a = s[mid];
forin(i, from, min(to, mid)) {
ll val = -1e18;
if(mid - i + 1 >= m) {
val = get(tr[i - 1], tr[mid]) - 2 * (p[mid].c - p[i].c);
}
if(a < val) {
a = val;
nxt = i;
}
}
solve(from, nxt, f, mid - 1);
solve(nxt, to, mid + 1, l);
}
int main () {
cin.tie(0)->sync_with_stdio(0);
if(fopen("Task.inp","r")) {
freopen("Task.inp","r",stdin);
freopen("WA.out","w",stdout);
}
cin>>n>>m;
forin(i, 1, n) cin>>p[i].v>>p[i].c;
sort(p + 1, p + n + 1, [] (piece a, piece b) {
return a.v < b.v;
});
forin(i, 1, n) p[i].i = i;
sort(p + 1, p + n + 1, [] (piece a, piece b) {
return a.c < b.c;
});
tr.resize(n + 1);
tr[0] = new it();
forin(i, 1, n) {
tr[i] = new it(*tr[i - 1]);
tr[i] -> up(p[i].i, p[i].v);
s[i] = -inf;
}
solve();
ans = -inf;
forin(i, 1, n) ans = max(ans, s[i]);
cout<<ans;
}
