#ifndef ONLINE_JUDGE
#define _GLIBCXX_DEBUG
#endif

#define _USE_MATH_DEFINES
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
//https://boostjp.github.io/tips/multiprec-int.html

#define YES cout<<"Yes\n"
#define NO cout<<"No\n"
#define YN {cout<<"Yes\n";}else{cout<<"No\n";}// if(a==b)YN;
#define NO2 cout<<"-1\n"

#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define rrep(i, n) for (int i=int(n)-1; i>=0; --i)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int N, M;
    cin>>N>>M;
    priority_queue<ll, vector<ll>, greater<ll>> pq;
    while(M--) pq.push(0);
    while(N--) {
        ll cur = pq.top(); pq.pop();
        ll T;
        cin>>T;
        pq.push(cur+T);
    }

    ll ans = 0;
    while(pq.size()) {
        ans = max(ans, pq.top());
        pq.pop();
    }
    cout << ans << endl;
}