//@formatter:off
#include<bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < int(n); ++i)
#define rrep(i,n) for (int i = int(n)-1; i >= 0; i--)
#define rep2(i,s,n) for (int i = int(s); i < int(n); ++i)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define pb push_back
#define eb emplace_back
#define vi vector<int>
#define vvi vector<vector<int>>
#define vl vector<ll>
#define vvl vector<vector<ll>>
#define vd vector<double>
#define vvd vector<vector<double>>
#define vs vector<string>
#define vc vector<char>
#define vvc vector<vector<char>>
#define vb vector<bool>
#define vvb vector<vector<bool>>
#define vp vector<P>
#define vvp vector<vector<P>>
using namespace std;
using ll = long long;
using P = pair<int,int>;
using LP = pair<ll,ll>;
template<class S,class T> istream& operator>>(istream &is,pair<S,T> &p) { return is >> p.first >> p.second; }
template<class S,class T> ostream& operator<<(ostream &os,const pair<S,T> &p) { return os<<'{'<<p.first<<","<<p.second<<'}'; }
template<class T> istream& operator>>(istream &is,vector<T> &v) { for(T &t:v){is>>t;} return is; }
template<class T> ostream& operator<<(ostream &os,const vector<T> &v) { os<<'[';rep(i,v.size())os<<v[i]<<(i==int(v.size()-1)?"":","); return os<<']'; }
void Yes(bool b) { cout << (b ? "Yes" : "No") << '\n'; }
void YES(bool b) { cout << (b ? "YES" : "NO") << '\n'; }
template<class T> bool chmin(T& a,T b) {if(a > b){a = b; return true;} return false;}
template<class T> bool chmax(T& a,T b) {if(a < b){a = b; return true;} return false;}
const int inf = 1001001001;
const ll linf = 1001001001001001001;
//@formatter:on

ll v[20][100010];
int to[20][100010];

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    int n, K;
    cin >> n >> K;
    vi a(n);
    cin >> a;
    ll sum = accumulate(all(a), 0LL);
    rep(i, n) a.pb(a[i]);
    ll ok = 1, ng = sum + 1;
    auto f = [&](ll x) {
        ll now = 0;
        int r = 0;
        rep(i, n) {
            while (now < x) now += a[r++];
            v[0][i] = r - i;
            to[0][i] = r % n;
            now -= a[i];
        }
        rep(k, 19) {
            rep(i, n) {
                v[k + 1][i] = v[k][i] + v[k][to[k][i]];
                to[k + 1][i] = to[k][to[k][i]];
            }
        }
        rep(i, n) {
            int pos = i;
            ll len = 0;
            int nk = K, k = 0;
            while (nk > 0) {
                if (nk & 1) {
                    len += v[k][pos];
                    pos = to[k][pos];
                }
                k++;
                nk >>= 1;
            }
            if(len <= n) return true;
        }
        return false;
    };
    while (abs(ok - ng) > 1) {
        ll mid = (ng + ok) / 2;
        if (f(mid)) ok = mid;
        else ng = mid;
    }
    cout << ok << endl;
}