/**
____ ____ ____ ____ ____ ____
||l |||e |||i |||n |||a |||d ||
||__|||__|||__|||__|||__|||__||
|/__\|/__\|/__\|/__\|/__\|/__\|
**/
#include<bits/stdc++.h>
#define endl '\n'
using namespace std;
typedef long long ll;
void speed()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
}
const int maxn = 2e5 + 10;
struct element
{
ll v, s, idx;
element(ll _v = 0, ll _s = 0, ll _idx = 0)
{
v = _v;
s = _s;
idx = _idx;
}
} e[maxn];
int n, m;
void input()
{
cin >> n >> m;
for (int i = 1; i <= n; i ++)
{
cin >> e[i].v >> e[i].s;
e[i].s *= 2;
e[i].idx = i;
}
}
bool cmp_second(element e1, element e2)
{
return e1.s < e2.s;
}
ll inf = 1e18;
ll result;
ll dp[maxn];
int lb = 1, rb = 0;
int tree[4 * maxn];
void update(int root, int left, int right, int pos, int val)
{
if (left == right)
{
tree[root] = val;
return;
}
int mid = (left + right) / 2;
if (pos <= mid)
update(root * 2, left, mid, pos, val);
else
update(root * 2 + 1, mid + 1, right, pos, val);
tree[root] = tree[root * 2] + tree[root * 2 + 1];
}
int walk(int root, int left, int right, int take)
{
if (left == right)
return left;
int mid = (left + right) / 2;
if (tree[root * 2 + 1] >= take)
return walk(root * 2 + 1, mid + 1, right, take);
else
return walk(root * 2, left, mid, take - tree[root * 2 + 1]);
}
int rev[maxn];
ll num[maxn];
ll fen[maxn];
void point_add(int pos, ll v)
{
for (int i = pos; i <= n; i += (i & -i))
fen[i] += v;
}
ll fen_sum(int pos)
{
ll s = 0;
for (int i = pos; i > 0; i -= (i & -i))
s += fen[i];
return s;
}
ll range_sum(int l, int r)
{
return fen_sum(r) - fen_sum(l - 1);
}
ll cost(int left, int right)
{
///cout << "cost" << endl;
while(rb < right)
{
rb ++;
update(1, 1, n, rev[rb], 1);
point_add(rev[rb], num[rev[rb]]);
}
while(lb > left)
{
lb --;
update(1, 1, n, rev[lb], 1);
point_add(rev[lb], num[rev[lb]]);
}
while(rb > right)
{
update(1, 1, n, rev[rb], 0);
point_add(rev[rb], -num[rev[rb]]);
rb --;
}
///cout << "fine" << endl;
while(lb < left)
{
update(1, 1, n, rev[lb], 0);
point_add(rev[lb], -num[rev[lb]]);
lb ++;
}
int pivot = walk(1, 1, n, m);
return range_sum(pivot, n);
//cout << "cost " << left << " " << right << endl;
/**vector < ll > values;
for (int i = left; i <= right; i ++)
values.push_back(e[i].v);
sort(values.begin(), values.end());
ll res = 0;
for (int i = (int)(values.size()) - 1; i >= (int)(values.size()) - m; i --)
res += values[i];
//exit(0);
return res;*/
}
void divide(int l, int r, int optl, int optr)
{
if (l > r)
return;
///cout << l << " " << r << " " << optl << " " << optr << endl;
int mid = max(optl + m - 1, (l + r) / 2), opt = -1;
if (mid > r)
return;
for (int i = optl; i <= min(optr, mid); i ++)
{
///cout << "check " << mid << " " << i << endl;
if (mid - i + 1 >= m)
{
ll sum = - e[mid].s + e[i].s + cost(i, mid);
///cout << "alive " << " " << sum << endl;
if (sum > dp[mid])
{
dp[mid ] = sum;
opt = i;
}
}
}
//cout << "pos " << mid << " " << opt << endl;
divide(l, mid - 1, optl, opt);
divide(mid + 1, r, opt, optr);
}
void print()
{
ll best = -inf;
for (int i = 1; i <= n; i ++)
best = max(best, dp[i]);
cout << best << endl;
}
void precompute()
{
sort(e + 1, e + n + 1, cmp_second);
vector < pair < ll, ll > > val;
for (int i = 1; i <= n; i ++)
{
e[i].idx = i;
val.push_back({e[i].v, i});
}
sort(val.begin(), val.end());
for (int i = 0; i < n; i ++)
{
rev[val[i].second] = i + 1;
num[i + 1] = val[i].first;
}
for (int i = 1; i <= n; i ++)
dp[i] = -inf;
}
void solve()
{
input();
precompute();
divide(1, n, 1, n);
print();
}
int main()
{
speed();
solve();
return 0;
}
