#include <bits/stdc++.h> using namespace std; #define POPCOUNT(n) (__builtin_popcountll((n))) #define CLZ(n) (__builtin_clzll((n))) #define CTZ(n) (__builtin_ctzll((n))) #define LOG(n) (63 - __builtin_clzll((n))) #define BIT(n, i) (((n) >> (i)) & 1ll) #define MASK(i) (1ll << (i)) #define FLIP(n, i) ((n) ^ (1ll << (i))) #define ON(n, i) ((n) | MASK(i)) #define OFF(n, i) ((n) & ~MASK(i)) #define Int __int128 #define fi first #define se second typedef long long ll; typedef unsigned long long ull; typedef long double ld; typedef pair<int, int> pii; typedef pair<long long, long long> pll; typedef pair<long long, int> pli; typedef pair<int, long long> pil; typedef vector<pair<int, int>> vii; typedef vector<pair<long long, long long>> vll; typedef vector<pair<long long, int>> vli; typedef vector<pair<int, long long>> vil; template <class T1, class T2> bool maximize(T1 &x, T2 y) { if (x < y) { x = y; return true; } return false; } template <class T1, class T2> bool minimize(T1 &x, T2 y) { if (x > y) { x = y; return true; } return false; } template <class T> void remove_duplicate(vector<T> &ve) { sort (ve.begin(), ve.end()); ve.resize(unique(ve.begin(), ve.end()) - ve.begin()); } mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count()); long long random(long long l, long long r) { return uniform_int_distribution<long long>(l, r)(rng); } unsigned long long random(unsigned long long l, unsigned long long r) { return uniform_int_distribution<unsigned long long>(l, r)(rng); } template <class T> T random(T r) { return rng() % r; } const int N = 1e6 + 5; const int MOD = 1e9 + 7; const int inf = 1e9; const long long INF = 1e18; int n, m; pii pieces[N]; ll pref[N]; signed main() { ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); cin >> n >> m; for (int i = 1; i <= n; ++i) { int v, c; cin >> v >> c; pieces[i] = make_pair(c, v); } sort (pieces + 1, pieces + 1 + n); for (int i = 1; i <= n; ++i) pref[i] = pref[i - 1] + pieces[i].se; ll ans = 0; for (int i = m; i <= n; ++i) { ll sum = pref[i] - pref[i - m]; int diff = pieces[i].fi - pieces[i - m + 1].fi; maximize(ans, sum - 2 * diff); } cout << ans; return 0; }