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

int main() {
    int N, K;
    cin >> N >> K;
    vector<int> A(2*N+1);
    int sum_A = 0;
    for (int i = 1; i < N+1; i++) {
        cin >> A[i];
        A[i+N]=A[i];
        sum_A += A[i];
    }
    for (int i = 1; i < 2*N+1; i++) {
        A[i] += A[i-1];
    }
    int ok = 0, ng = sum_A / K+1;
    while (abs(ok-ng) > 1) {
        int mid = (ok+ng) / 2;
        vector<int> perm(2*N+1);
        for (int i = 0; i < 2*N+1; i++) {
            perm[i] = i;
        }
        int r = 0;
        for (int l = 0; l < 2*N; l++) {
            while (r < 2*N && A[r]-A[l] < mid) {
                r++;
            }
            perm[l] = r;
        }
        int k = log2(K) + 1;
        vector<vector<int>> perm_doub(2*N+1, vector<int>(k));
        for (int n = 0; n < 2*N+1; n++) {
            perm_doub[n][0] = perm[n];
        }
        for (int kk = 1; kk < k; kk++) {
            for (int n = 0; n < 2*N+1; n++) {
                perm_doub[n][kk] = perm_doub[perm_doub[n][kk-1]][kk-1];
            }
        }
        bool found = false;
        for (int i = 0; i < N; i++) {
            int x = i;
            for (int kk = 0; kk < k; kk++) {
                if (K>>kk & 1) {
                    x = perm_doub[x][kk];
                }
            }
            if (mid < A[i]) {
                break;
            }
            if (i + 1 <= x && x <= i + N) {
                found = true;
                break;
            }
        }
        if(found){
            ok=mid;
        }
        else{
            ng = mid;
        }
    }
    cout << ok << endl;
    return 0;
}