//#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
#define rep(i, n) for(int i=0; i<n; ++i)
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
using namespace std;
using ll = int64_t;
using ld = long double;
using P = pair<int, int>;
using vs = vector<string>;
using vi = vector<int>;
using vvi = vector<vi>;
template<class T> using PQ = priority_queue<T>;
template<class T> using PQG = priority_queue<T, vector<T>, greater<T> >;
const int INF = 0xccccccc;
const ll LINF = 0xcccccccccccccccLL;
template<typename T1, typename T2>
inline bool chmax(T1 &a, T2 b) {return a < b && (a = b, true);}
template<typename T1, typename T2>
inline bool chmin(T1 &a, T2 b) {return a > b && (a = b, true);}
template<typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) { return is >> p.first >> p.second;}
template<typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) { return os << p.first << ' ' << p.second;}

#define N 100010

//head

int n, k;
int a[N];
ll summ;
ll sum[N<<1];
int ma = INF, ar;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> n >> k;
  rep(i, n) cin >> a[i];
  summ = accumulate(a, a+n, 0LL);
  if(k == 1) {
    cout << summ << endl;
    return 0;
  }
  rep(i, n<<1) sum[i+1] = sum[i] + a[i%n];
  rep(i, n) {
    ll *itr = lower_bound(sum+i, sum+n+i, sum[i]+summ/k+1);
    if(chmin(ma, itr-sum-i)) ar = i;
  }
  rotate(a, a+ar, a+n);
  rep(i, n<<1) sum[i+1] = sum[i] + a[i%n];
  ll ub = summ/k+1, mid, lb = 0;
  while(ub-lb != 1) {
    mid = (ub+lb)>>1;
    bool ok = false;
    rep(i, ma) {
      int j = 0;
      bool nok = true;
      rep(kk, k) {
        ll *itr = lower_bound(sum+i+j, sum+n*2, sum[i+j]+mid);
        j = itr-sum-i;
        if(j > n) {
          nok = false;
          break;
        }
      }
      if(nok) {
        ok = true;
        break;
      }
    }
    if(ok) {
      lb = mid;
    }
    else {
      ub = mid;
    }
  }
  cout << lb << endl;
}