#include <bits/stdc++.h>
#define f first
#define s second
using namespace std;
typedef long long ll;
const int N = 4e5+5;
ll n, k, cn, ans = -1e18;
ll root[N], lc[N*4], rc[N*4];
pair<ll, ll> tree[N*4];
vector<int> comp;
pair<ll, ll> p[N];
void merge(int node)
{
tree[node].f = tree[lc[node]].f+tree[rc[node]].f;
tree[node].s = tree[lc[node]].s+tree[rc[node]].s;
}
void build(int node = 0, int l=0, int r=n-1)
{
if(l == r)
{
tree[node] = {1, comp[l]};
//cout << node << " " << tree[node].f << " " << tree[node].s << " | " << l << " " << r << endl;
return ;
}
int mid = (l+r)>>1;
lc[node] = ++cn, rc[node] = ++cn;
build(lc[node], l, mid);
build(rc[node], mid+1, r);
merge(node);
//cout << node << " " << tree[node].f << " " << tree[node].s << " | " << l << " " << r << endl;
}
void upd(int i, int node, int node2, int l=0, int r=n-1)
{
if(l == r)
{
tree[node] = {0, 0};
//cout << node << " " << tree[node].f << " " << tree[node].s << " | " << l << " " << r << endl;
return ;
}
int mid = (l+r)>>1;
if(i > mid)
{
rc[node] = ++cn;
lc[node] = lc[node2];
upd(i, rc[node], rc[node2], mid+1, r);
}
else
{
rc[node] = rc[node2];
lc[node] = ++cn;
upd(i, lc[node], lc[node2], l, mid);
}
merge(node);
//cout << node << " " << tree[node].f << " " << tree[node].s << " | " << l << " " << r << endl;
}
bool cmp(pair<ll, ll> a, pair<ll, ll> b)
{
return a.s < b.s;
}
ll sum2(ll l, ll r)
{
vector<ll> vec;
ll ret = 0;
for(ll i=l; i<=r; i++)
{
vec.push_back(p[i].f);
}
sort(vec.rbegin(), vec.rend());
for(ll i=0; i<k; i++) ret += vec[i];
return ret;
}
ll sum(int node1, int node2, ll cnt)
{
ll cmt = tree[rc[node2]].f-tree[rc[node1]].f;
//cout << node1 << " " << node2 << " | " << rc[node1] << " " << lc[node1]
// << " | " << cmt << " " << cnt << " " << tree[node2].f-tree[node1].f << endl;
//assert(tree[node2].f-tree[node1].f >= cnt);
if(tree[node2].f-tree[node1].f == cnt) return tree[node2].s-tree[node1].s;
if(!cnt) return 0;
else if(cmt >= cnt) return sum(rc[node1], rc[node2], cnt);
else return sum(rc[node1], rc[node2], cmt) + sum(lc[node1], lc[node2], cnt-cmt);
}
void solve(ll l, ll r, ll s, ll e)
{
if(l > r) return ;
ll id = -1, m = -1e18;
ll mid = (l+r)>>1;
for(ll i=max(mid+k-1, (ll)s); i<=e; i++)
{
ll tmp;
if(tree[root[mid]].f-tree[root[i+1]].f >= k) tmp = sum(root[i+1], root[mid], k);
tmp = sum2(mid, i);
tmp -= (p[i].s-p[mid].s)*2LL;
if(tmp > m) m = tmp, id = i;
}
solve(l, mid-1, s, id);
solve(mid+1, r, id, e);
ans = max(ans, m);
}
int main()
{
cin >> n >> k;
for(int i=0; i<n; i++) cin >> p[i].f >> p[i].s, comp.push_back(p[i].f);
sort(comp.begin(), comp.end());
sort(p, p+n, cmp);
build();
for(int i=1; i<=n; i++)
{
int id = lower_bound(comp.begin(), comp.end(), p[i-1].f)-comp.begin();
root[i] = ++cn;
upd(id, root[i], root[i-1]);
}
solve(0, n-k, 0, n-1);
cout << ans << endl;
}
