#include <bits/stdc++.h> using namespace std; #pragma GCC optimize("O3,unroll-loops") #define int long long #define ii pair<int,int> #define fir first #define sec second #define pb push_back signed main(){ ios_base::sync_with_stdio(0); cin.tie(0);cout.tie(0); int n,m; cin>>n>>m; ii apa[n+1]; for(int q=1;q<=n;q++){ cin>>apa[q].sec>>apa[q].fir; } sort(apa+1,apa+n+1); int ans=-1e18; for(int q=1;q<=n-m+1;q++){ int tot=apa[q].sec+2*apa[q].fir; priority_queue<int,vector<int>,greater<int> >pq; for(int w=q+1;w<=n;w++){ pq.push(apa[w].sec); tot+=apa[w].sec; if(pq.size()>m-1){ tot-=pq.top(); pq.pop(); } if(pq.size()>=m-1){ ans=max(ans,tot-2*apa[w].fir); } } } cout<<ans<<endl; }