#include<iostream>
#include<fstream>
using namespace std;

int main(){
	ifstream f("transport.in");
	int n = 0, k = 0;
	f >> n >> k;
	int saltele[16000];
	int max = 0;
	for (int i = 0; i < n; i++){
		f>>saltele[i];
		if (saltele[i]>max){
			max = saltele[i];
		}
	}
	int s = saltele[0], l = 0;
	for (int i = 1; i < n; i++){
		if (s + saltele[i] <= max){
			s += saltele[i];
		}
		else{
			if (l < k-1){
				s = saltele[i];
				l++;
			}
			else{
				l = 0;
				i = 1;
				s = saltele[0];
				max++;
			}
		}
	}
	ofstream o("transport.out");
	o << max;
	return 0;
}