#include <bits/stdc++.h>
using namespace std;
const long long INF = 1e18;
int main()
{
cin.tie(0)->sync_with_stdio(0);
int n, K;
cin >> n >> K;
vector<pair<int, int>> a(n);
for (int i = 0; i < n; i++)
{
cin >> a[i].second >> a[i].first;
}
sort(a.begin(), a.end());
long long cur = 0;
multiset<int> st, st2;
auto add = [&](int x)
{
st.insert(x);
cur += x;
while (st.size() > K)
{
auto it = st.begin();
cur -= *it;
st2.insert(*it);
st.erase(it);
}
};
auto del = [&](int x)
{
auto it = st.find(x);
if (it == st.end())
{
it = st2.find(x);
st2.erase(x);
}
else
{
cur -= *it;
st.erase(it);
while (st2.size() && st.size() < K)
{
it = --st2.end();
cur += *it;
st.insert(*it);
st2.erase(it);
}
}
};
int ll = 0, rr = -1;
auto query = [&]() -> long long
{
return st.size() == K ? cur : -INF;
};
long long ans = -INF;
function<void(int, int, int, int)> solve = [&](int l, int r, int ql, int qr)
{
if (l > r)
{
return;
}
int mid = (l + r) / 2;
pair<long long, int> maxn(-INF, -1);
while (rr < mid)
{
add(a[++rr].second);
}
while (ll > qr)
{
add(a[--ll].second);
}
while (rr > mid && rr >= ll)
{
del(a[rr--].second);
}
while (ll < qr && ll <= rr)
{
del(a[ll++].second);
}
while (ll > ql)
{
maxn = max(maxn, make_pair(query() - 2ll * (a[mid].first - a[ll].first), ll));
add(a[--ll].second);
}
maxn = max(maxn, make_pair(query() - 2ll * (a[mid].first - a[ll].first), ll));
auto [mx, j] = maxn;
ans = max(ans, mx);
solve(l, mid - 1, ql, j);
solve(mid + 1, r, j, qr);
};
solve(K - 1, n - 1, 0, n - 1);
cout << ans << '\n';
return 0;
}
