#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, s, e) for (int i = (int)(s); i < (int)(e); ++i)

int main() {
	cin.tie(nullptr);
	ios_base::sync_with_stdio(false);
	
	int N, M;
	cin >> N >> M;
	
	priority_queue<ll, vector<ll>, greater<ll>> que;
	rep(i, 0, M) que.push(0);
	
	rep(i, 0, N) {
		ll T;
		cin >> T;
		
		ll v = que.top() + T;
		que.pop();
		que.push(v);
		
		if (i == N - 1) cout << v << '\n';
	}
}