#include <iostream>
#include <vector>
#include <bitset>

using namespace std;

vector<long long> elem;
int n, k;

bool check_fits(bitset<57> val, int pref, long long check) {
    bitset<57> checkset(check);

    for (int i = 1; i <= pref; i++) {
        if (val[57 - i] && !checkset[57 - i]) {
            return false;
        }
    }
    //cout << "Checfit for " << check << endl;
    return true;
}

bool check_for_pref(bitset<57> val, int pref, bool log = false) {
    //if (log)
    //    cout << "Checkprefing with " << val.to_string() << " " << pref << endl;

    vector<vector<bool>> dp(n + 1, vector<bool>(k + 1));
    dp[0][0] = true;
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= k; j++) {
            long long sum = 0;
            for (int seg = 1; seg <= i && !dp[i][j]; seg++) {
                sum += elem[i - seg];
                dp[i][j] = dp[i][j] | (dp[i - seg][j - 1] && check_fits(val, pref, sum));
            }
        }
    }

    /*if (log) {
        for (int i = 0; i <= n; i++) {
            for (int j = 0; j <= k; j++) {
                cout << dp[i][j] << " ";
            }
            cout << endl;
        }
    }*/

    return dp[n][k];
}

bool check(long long checkval) {
    //cout << "Checking " << checkval << endl;
    bitset<57> val(checkval);
    //cout << val.to_string() << endl;
    for (int i = 1; i <= 57; i++) {
        if (val[57 - i] == 0) {
            bitset<57> newval = val;
            newval[57 - i] = true;
            if (check_for_pref(newval, i)) {
                //check_for_pref(newval, i, true);
                return true;
            }
        }
    }
    return false;
}


int main() {
    cin >> n >> k;
    elem.resize(n);
    for (int i = 0; i < n; i++) {
        cin >> elem[i];
    }

    long long l = -1, r = ((unsigned long long)1 << (unsigned long long)56);
    while (r > l + 1) {
        long long m = (l + r) / 2;
        if (check(m)) {
            l = m;
        } else {
            r = m;
        }
    }
    cout << r << endl;

    return 0;
}