/*input
5 3
2 1
4 2
6 4
8 8
10 16
*/
#include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
using namespace std;
const int MAXN = 200007, LOG = __lg(MAXN) + 1;
const int64_t INF = 1e17;
int64_t bit_sum[MAXN];
int bit_cnt[MAXN];
void add(int i, int64_t x)
{
for (; i < MAXN; i += i & (-i)) bit_sum[i] += x, ++bit_cnt[i];
}
void rem(int i, int64_t x)
{
for (; i < MAXN; i += i & (-i)) bit_sum[i] -= x, --bit_cnt[i];
}
int64_t get(int k)
{
int64_t ans = 0;
for (int i = 0, j = LOG - 1; j >= 0; --j) {
if ((i | (1 << j)) < MAXN && bit_cnt[i | (1 << j)] <= k) {
i |= (1 << j);
k -= bit_cnt[i];
ans += bit_sum[i];
}
}
return ans;
}
int N, M;
int64_t ans = -INF;
int sortedC[MAXN], rankC[MAXN];
pair<int, int> cakes[MAXN];
int ptr_l = 0, ptr_r = -1;
int64_t calc(int l, int r)
{
if (l + M - 1 > r) return -INF;
while (ptr_l < l) rem(rankC[ptr_l], cakes[ptr_l].second), ++ptr_l;
while (ptr_l > l) --ptr_l, add(rankC[ptr_l], cakes[ptr_l].second);
while (ptr_r > r) rem(rankC[ptr_r], cakes[ptr_r].second), --ptr_r;
while (ptr_r < r) ++ptr_r, add(rankC[ptr_r], cakes[ptr_r].second);
return get(M) - 2ll * (cakes[r].first - cakes[l].first);
}
void solve(int opt_l, int opt_r, int l, int r)
{
if (l > r) return;
if (opt_l == opt_r) {
for (int i = l; i <= r; ++i) ans = max(ans, calc(opt_l, i));
return;
}
int m = (l + r) >> 1;
int opt_m = opt_l;
int64_t ans_m = calc(opt_m, m);
for (int i = opt_l + 1; i <= opt_r; ++i) {
int64_t cur = calc(i, m);
if (cur > ans_m) {
ans_m = cur;
opt_m = l;
}
}
ans = max(ans, ans_m);
solve(opt_l, opt_m, l, m - 1);
solve(opt_m, opt_r, m + 1, r);
}
int main()
{
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> N >> M;
for (int i = 0; i < N; ++i) {
cin >> cakes[i].second >> cakes[i].first;
}
sort(cakes, cakes + N);
iota(sortedC, sortedC + N, 0);
sort(sortedC, sortedC + N, [&](int i, int j) { return cakes[i].second > cakes[j].second; });
for (int i = 0; i < N; ++i) rankC[sortedC[i]] = i + 1;
solve(0, N - 1, 0, N - 1);
cout << ans << endl;
return 0;
}
