#define taskname "test"
#include <bits/stdc++.h>
using namespace std;
#define sz(x) (int)x.size()
#define fi first
#define se second
typedef long long lli;
typedef pair<int, int> pii;
const int maxn = 2e5 + 5;
const lli inf = 1e18;
int n, m;
pii cakes[maxn];
vector<int> vals;
lli f[maxn];
struct segment_tree
{
lli total[maxn * 4];
int cnt[maxn * 4];
void update(int x, int l, int r, int p, int k)
{
if(l == r)
{
total[x] += vals[l - 1] * k;
cnt[x] += k;
return;
}
int mid = (l + r) / 2;
if(p <= mid) update(x * 2, l, mid, p, k);
else update(x * 2 + 1, mid + 1, r, p, k);
total[x] = total[x * 2] + total[x * 2 + 1];
cnt[x] = cnt[x * 2] + cnt[x * 2 + 1];
}
lli get(int x, int l, int r, int k)
{
if(l == r) return vals[l] * 1LL * min(k, cnt[x]);
int mid = (l + r) / 2;
if(cnt[x * 2 + 1] <= k)
return total[x * 2 + 1] + get(x * 2, l, mid, k - cnt[x * 2 + 1]);
else return get(x * 2 + 1, mid + 1, r, k);
}
} tree;
void read_input()
{
cin >> n >> m;
for(int i = 1; i <= n; ++i)
cin >> cakes[i].fi >> cakes[i].se;
}
void init()
{
sort(cakes + 1, cakes + n + 1, [](pii p, pii q)
{
return p.se < q.se;
});
for(int i = 1; i <= n; ++i)
vals.push_back(cakes[i].fi);
sort(vals.begin(), vals.end());
vals.erase(unique(vals.begin(), vals.end()), vals.end());
for(int i = 1; i <= n; ++i)
cakes[i].fi = lower_bound(vals.begin(), vals.end(), cakes[i].fi) - vals.begin() + 1;
}
lli query(int l, int r)
{
static int curl = 1, curr = 0;
while(curr < r)
{
++curr;
tree.update(1, 1, sz(vals), cakes[curr].fi, 1);
}
while(curr > r)
{
tree.update(1, 1, sz(vals), cakes[curr].fi, -1);
--curr;
}
while(curl > l)
{
--curl;
tree.update(1, 1, sz(vals), cakes[curl].fi, 1);
}
while(curl < l)
{
tree.update(1, 1, sz(vals), cakes[curl].fi, -1);
++curl;
}
return tree.get(1, 1, sz(vals), m - 2);
}
void dnc(int l, int r, int optl, int optr)
{
if(l > r) return;
int mid = (l + r) / 2;
lli best = -inf;
int opt = 0;
for(int i = max(mid + m - 1, optl); i <= optr; ++i)
{
lli k = query(mid + 1, i - 1) + vals[cakes[mid].fi - 1] + vals[cakes[i].fi - 1] - 2LL * (cakes[i].se - cakes[mid].se);
if(k > best)
{
best = k;
opt = i;
}
}
f[mid] = best;
dnc(l, mid - 1, optl, opt);
dnc(mid + 1, r, opt, optr);
}
void solve()
{
dnc(1, n - m + 1, 1, n);
lli ans = -inf;
for(int i = 1; i <= n - m + 1; ++i)
ans = max(ans, f[i]);
cout << ans << '\n';
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
read_input();
init();
solve();
}
