#include<bits/stdc++.h>
using namespace std;

int main(){
  using ll=long long;
  int n,m;
  cin>>n>>m;
  priority_queue<pair<ll,int>> q;
  for (int i=0;i<m;i++) q.push({0,-i});
  ll ans=0;
  for (int i=0;i<n;i++){
    ll t;
    cin>>t;
    auto [s,v]=q.top();
    q.pop();
    q.push({s-t,v});
    ans=max(ans,-(s-t));
  }
  cout<<ans<<endl;
}