#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define MASK(i) (1ULL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
ll gcd(ll a, ll b){return __gcd(a, b);}
ll lcm(ll a, ll b){return a / gcd(a, b) * b;}
ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ull mask){return __builtin_popcountll(mask);}
int ctz(ull mask){return __builtin_ctzll(mask);}
int logOf(ull mask){return 63 - __builtin_clzll(mask);}
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rngesus(ll l, ll r){return l + (ull) rng() % (r - l + 1);}
double rngesus_d(double l, double r){
double cur = rngesus(0, MASK(60) - 1);
cur /= MASK(60) - 1;
return l + cur * (r - l);
}
template <class T1, class T2>
bool maximize(T1 &a, T2 b){
if (a < b) {a = b; return true;}
return false;
}
template <class T1, class T2>
bool minimize(T1 &a, T2 b){
if (a > b) {a = b; return true;}
return false;
}
template <class T>
void printArr(T container, string separator = " ", string finish = "\n", ostream &out = cout){
for(auto item: container) out << item << separator;
out << finish;
}
template <class T>
void remove_dup(vector<T> &a){
sort(ALL(a));
a.resize(unique(ALL(a)) - a.begin());
}
struct FenwickTree{
int n;
vector<ll> a;
FenwickTree(int _n){
n = _n;
a.resize(n+1);
}
void update(int i, ll v){
while(i <= n){
a[i] += v;
i += LASTBIT(i);
}
}
ll get(int i){
ll ans = 0;
while(i > 0){
ans += a[i];
i -= LASTBIT(i);
}
return ans;
}
ll get(int l, int r){return get(r) - get(l-1);}
int binary_lift(ll x){
int p = MASK(logOf(n)), idx =0;
while(p > 0){
if (idx + p <= n && x > a[idx + p]){
idx += p;
x -= a[idx];
}
p >>= 1;
}
return idx + 1;
}
};
const int N = 2e5 + 69;
const ll INF = 1e18 + 69;
int n, m;
FenwickTree bit(N), sum(N);
int L = 1, R = 0;
ll cost[N];
vector<pair<int, int>> val;
vector<pair<int, int>> a;
void update_idx(int i, int mul){
i = a[i].first;
bit.update(i, mul);
sum.update(i, val[i].first * mul);
}
ll calc_cost(int l, int r){
while(R < r)
update_idx(++R, 1);
while(L > l)
update_idx(--L, 1);
while(R > r)
update_idx(R--, -1);
while(L < l)
update_idx(L++, -1);
return sum.get(bit.binary_lift(m)) - (a[r].second - a[l].second) * 2;
}
void dnc(int l, int r, int optL, int optR){
if (l > r) return;
int mid = (l + r) >> 1;
int opt = -1;
if (R <= max(optL, mid + m - 1)) {
for(int i = max(optL, mid + m - 1); i <= optR; ++i){
if (maximize(cost[mid], calc_cost(mid, i)))
opt = i;
}
}
else{
for(int i = optR; i >= max(optL, mid + m - 1); --i){
if (maximize(cost[mid], calc_cost(mid, i)))
opt = i;
}
}
dnc(l, mid - 1, optL, opt);
dnc(mid + 1, r, opt, optR);
}
void solve(){
cin >> n >> m;
a.resize(n);
for(int i = 0; i < n; ++i) cin >> a[i].first >> a[i].second;
a.push_back({-1, -1});
sort(ALL(a), [](pair<int, int> x, pair<int, int> y){return x.second < y.second;});
val.push_back({1e9 + 69, 0});
for(int i = 1; i <= n; ++i) val.push_back({a[i].first, i});
sort(ALL(val), greater<pair<int, int>>());
for(int i = 1; i <= n; ++i) a[val[i].second].first = i;
for(int i = 1; i<= n; ++i) cost[i] = -INF;
dnc(1, n - m + 1, m, n);
ll ans = -INF;
for(int i = 1; i <= n - m + 1; ++i) maximize(ans, cost[i]);
cout << ans << "\n";
}
int main(void){
ios::sync_with_stdio(0);cin.tie(0); cout.tie(0);
clock_t start = clock();
solve();
cerr << "Time elapsed: " << clock() - start << " ms\n";
return 0;
}
