#include "bits/stdc++.h"
#define rep(i,n)for(int i=0;i<(int)(n);i++)
using namespace std;
#define all(a) a.begin(),a.end()
typedef long long ll;
typedef pair<ll,ll>P;
#define vi vector<ll>
const ll inf=1ll<<61;
ll a[100006];
ll rwa[200005];
ll to[20][100005];
signed main(){
	ll n,k;cin>>n>>k;
	ll S=0;
	rep(i,n){
		cin>>a[i];
		rwa[i+1]=rwa[i+n+1]=a[i];
		S+=a[i];
	}
	rep(i,n+n)rwa[i+1]+=rwa[i];

	ll lb=0,ub=(S/k)+1;
	while(ub-lb>1){
		//全員がmi以上保持できるか?
		ll mi=(ub+lb)/2;

		rep(i,n){
			auto itr=lower_bound(rwa,rwa+n+n+1,rwa[i]+mi);
			to[0][i]=itr-rwa;
			to[0][i+n]=to[0][i]+n;
			if(to[0][i+n]>=n+n)to[0][i+n]=n+n;
		}
		to[0][n+n]=n+n;
		rep(i,19){
			rep(j,n+n+1){
				to[i+1][j]=to[i][to[i][j]];
			}
		}
		int ok=0;
		rep(i,n){
			int now=i;
			rep(j,19){
				if(k&(1<<j))now=to[j][now];
			}
			if(i<now&&now<=i+n)ok++;
		}

		if(ok)lb=mi;
		else ub=mi;
	}
	cout<<lb<<endl;
}