#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
const int INF = 0x3f3f3f3f;
const ll LINF = 0x3f3f3f3f3f3f3f3fLL;
const double EPS = 1e-8;
const int MOD = 1000000007;
// const int MOD = 998244353;
const int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1};
const int dy8[] = {1, 1, 0, -1, -1, -1, 0, 1}, dx8[] = {0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U> inline bool chmax(T &a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U> inline bool chmin(T &a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(20);
  }
} iosetup;

int main() {
  const int X = 16;
  int n, k; cin >> n >> k;
  vector<ll> a(n * 2); REP(i, n) cin >> a[i];
  ll lb = *min_element(ALL(a)), ub = accumulate(ALL(a), 0LL) + 1;
  FOR(i, n, n * 2) a[i] = a[i - n];
  FOR(i, 1, n * 2) a[i] += a[i - 1];
  while (ub - lb > 1) {
    ll mid = (lb + ub) / 2;
    vector dp(X + 1, vector(n * 2, INF));
    REP(i, n) dp[0][i] = lower_bound(ALL(a), (i > 0 ? a[i - 1] : 0) + mid) - a.begin() + 1;
    FOR(i, n, n * 2) dp[0][i] = n + dp[0][i - n];
    REP(i, X) REP(j, n * 2) {
      if (dp[i][j] < n * 2) dp[i + 1][j] = dp[i][dp[i][j]];
    }
    bool sp = false;
    REP(i, n) {
      int pos = i;
      REP(j, X + 1) {
        if (pos < n * 2 && (k >> j & 1)) pos = dp[j][pos];
      }
      sp |= pos - i <= n;
    }
    (sp ? lb : ub) = mid;
  }
  cout << lb << '\n';
  return 0;
}