#include <bits/stdc++.h>
typedef long long ll;
#define f first
#define s second
#define pb push_back
#define ep emplace
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define uniquev(v) sort(all(v)), (v).resize(unique(all(v)) - (v).begin())
#define mem(f,x) memset(f , x , sizeof(f))
#define sz(x) (int)(x).size()
#define __lcm(a, b) (1ll * ((a) / __gcd((a), (b))) * (b))
#define mxx *max_element
#define mnn *min_element
#define cntbit(x) __builtin_popcountll(x)
using namespace std;
const int N = 2e5 + 100;
pair <ll, ll> seg[N * 4];
vector <ll> val;
vector <pair <ll, ll>> save;
map <int, int> mp;
void add(int id, int l, int r, int p, int val) {
if (l > p || r < p)
return;
if (val < 0) {
seg[id].s--;
} else {
seg[id].s++;
}
seg[id].f += val;
if (l == r)
return;
int m = (l + r) / 2;
add(id * 2, l, m, p, val);
add(id * 2 + 1, m + 1, r, p, val);
}
ll walk(int id, int l, int r, int re) {
if (l == r) {
return seg[id].f - val[l] * (seg[id].s - re);
}
int m = (l + r) / 2;
if (seg[id * 2].s >= re)
return walk(id * 2, l, m, re);
ll t = walk(id * 2 + 1, m + 1, r, re - seg[id * 2].s);
return seg[id * 2].f + t;
}
int n;
ll get(int m) {
return walk(1, 0, n - 1, m);
}
ll ans = -1e16;
int l = 0, r = 0, sz;
void move(int L, int R) {
while (r < R) {
r++;
add(1, 0, n - 1, save[r].s, val[save[r].s]);
}
while (l > L) {
l--;
add(1, 0, n - 1, save[l].s, val[save[l].s]);
}
while (l < L) {
add(1, 0, n - 1, save[l].s, -val[save[l].s]);
l++;
}
while (r > R) {
add(1, 0, n - 1, save[r].s, -val[save[r].s]);
r--;
}
}
void dnc(int l, int r, int opl, int opr) {
if (l > r || opl > opr)
return;
ll mx = -1e16;
int m = (l + r) / 2, opt = opr;
for (int j = max(m + sz - 1, opl); j <= opr; j++) {
move(m, j);
ll t = get(sz);
if (mx < t - (save[j].f - save[m].f) * 2) {
mx = t - (save[j].f - save[m].f) * 2;
opt = j;
}
}
dnc(l, m - 1, opl, opt);
dnc(m + 1, r, opt, opr);
ans = max(ans, mx);
}
ll solve() {
cin >> n >> sz;
for (int i = 0; i < n; i++) {
int v, c;
cin >> v >> c;
save.pb({c, v});
val.pb(v);
}
sort(all(save));
uniquev(val);
reverse(all(val));
for (int i = 0; i < sz(val); i++)
mp[val[i]] = i;
for (auto &x : save) {
x.s = mp[x.s];
}
l = r = 0;
add(1, 0, n - 1, save[0].s, val[save[0].s]);
dnc(0, n - 1, 0, n - 1);
return ans;
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t = 1;
//cin >> t;
while (t--) {
//solve();
cout << solve() << '\n';
}
return 0;
}
/*
4 3
2 3
2 6 2
2 4 2
6 5 1
1 2 3
*/
