bs5

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

const int maxN = 2 * 1e5 + 10;
long long a[maxN];
int n;

bool yes (long long block_limit,long long k) {
	long long sum = 0;
	long long count = 0;
	for (int i = 1; i <= n; ++i) {
		sum += a[i];
		if (sum > block_limit) {
			sum = a[i];
			++count;
		}
	}
	if (sum > 0) ++count;
	if (count <= k) return true;
	else return false;
}


int main () {
	 ios::sync_with_stdio(false);
	 cin.tie(nullptr);
	 cout.tie(nullptr);
	 long long k;
	 cin >> n >> k;
	 for (int i = 1; i <= n; ++i) cin >> a[i];
	 long long l = 0,r = 1e15;
	 for (int i = 1; i <= n; ++i) l = max(l,a[i]);
	 long long res = 0;
	 while (l <= r) {
		 long long m = l + (r - l) / 2;
		 if (yes(m,k)) {
			 res = m;
			 r = m - 1;
		 } else {
			 l = m + 1;
		 }
	 }
	 cout << res << '\n';
}