#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ii pair<int, int>
#define fi first
#define se second
#define ve vector
#define mini(a, b) a = min(a, b)
#define maxi(a, b) a = max(a, b)
#define all(x) x.begin(), x.end()
#define _ << ' ' <<
#define err(x) cerr << (#x) << " = " << (x) << '\n'
#define fo(i,a,b) for (int i = (a); i <= (b); ++i)
#define fd(i,a,b) for (int i = (a); i >= (b); --i)
#define pb push_back
#define siz(x) (int)((x).size())
#define ld long double
bool Mbe;
const int N = 2e5+5, M = 1e2+5, inf = 1e9+10, mod = 1e9+7;
struct node {
int cnt, lc, rc; ll sum;
node() {
cnt = lc = rc = sum = 0;
}
};
node t[N*19];
int he;
ve<int> z;
int clone(int p = 0) {
t[++he] = t[p];
return he;
}
void pull(int p) {
t[p].cnt = t[t[p].lc].cnt + t[t[p].rc].cnt;
t[p].sum = t[t[p].lc].sum + t[t[p].rc].sum;
}
int init(int p, int l, int r) {
int k = clone(p);
if (l == r) return k;
int mid = (l + r) >> 1;
t[k].lc = init(t[p].lc, l, mid);
t[p].rc = init(t[p].rc, mid+1, r);
return k;
}
int upd(int p, int l, int r, int pos, int val) {
int k = clone(p);
if (l == r) {
t[k].cnt++;
t[k].sum += val;
return k;
}
int mid = (l + r) >> 1;
if (pos <= mid) t[k].lc = upd(t[p].lc, l, mid, pos, val);
else t[k].rc = upd(t[p].rc, mid+1, r, pos, val);
pull(k);
return k;
}
ll get(int pL, int pR, int l, int r, int k) {
if (k == 0 || t[pL].cnt == t[pR].cnt) return 0;
if (k >= t[pR].cnt - t[pL].cnt) return t[pR].sum-t[pL].sum;
if (l == r) return min(k, t[pR].cnt - t[pL].cnt) * z[l-1];
int mid = (l + r) >> 1;
ll ans = get(t[pL].rc, t[pR].rc, mid+1, r, k);
k -= min(k, t[t[pR].rc].cnt - t[t[pL].rc].cnt);
return ans + get(t[pL].lc, t[pR].lc, l, mid, k);
}
int n, m, root[N];
ll get(int l, int r, int k) {
return get(root[l-1], root[r], 1, n, k);
}
ii a[N];
ll ans = -1e18;
ll cost(int l, int r) {
int nx = min(r-l+1, m);
return get(l, r, nx) - 2LL * (a[r].se - a[l].se);
}
void dnc(int l, int r, int optl, int optr) {
if (l > r) return;
int mid = (l + r) >> 1;
pair<ll,int> best={-1e18,-1};
fo(i,optl,min(mid-m+1,optr)) {
best=max(best,pair<ll,int>(cost(i, mid), i));
}
maxi(ans, best.fi);
if (best.se==-1) best.se=optl;
dnc(l, mid-1, optl, best.se);
dnc(mid+1, r, best.se, optr);
}
void solve() {
cin >> n >> m;
root[0] = clone(0);
root[0] = init(root[0], 1, n);
fo(i,1,n) {
cin >> a[i].fi >> a[i].se;
z.pb(a[i].fi);
}
sort(all(z)); z.resize(unique(all(z))-z.begin());
sort(a+1, a+n+1, [&](ii x, ii y)->bool{
if (x.se == y.se) return 0;
return x.se < y.se;
});
fo(i,1,n) {
a[i].fi = upper_bound(all(z), a[i].fi)-z.begin();
root[i] = upd(root[i-1], 1, n, a[i].fi, z[a[i].fi-1]);
}
dnc(1,n,1,n);
cout << ans;
}
bool Med;
signed main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
if (fopen("a.inp", "r")) {
freopen("a.inp", "r", stdin);
freopen("a.out", "w", stdout);
}
solve();
cerr << "mem = " << abs(&Med-&Mbe)/1024.0/1024.0 << " mb\n";
cerr << "time = " << clock()/1000.0 << "ms\n";
return 0;
}
