#line 1 "main.cpp"
#include <iostream>
#include <algorithm>
#include <vector>

using namespace std;
constexpr int INF = 1 << 30;

void solve() {
    int n, m;
    cin >> n >> m;

    auto xss = vector(n, vector(n, 0));
    for (auto& xs : xss) {
        for (auto& x : xs) cin >> x;
    }

    int ans = INF;
    for (int b = 0; b < 4; ++b) {
        auto yss = xss;
        int cost = 0, rem = m;

        if (b & 1) {
            --rem;
            for (int i = 0; i < n; ++i) {
                cost += yss[i][i];
                yss[i][i] = 0;
            }
        }
        if (b & 2) {
            --rem;
            for (int i = 0; i < n; ++i) {
                cost += yss[i][n - 1 - i];
                yss[i][n - 1 - i] = 0;
            }
        }

        for (int p = 0; p < (1 << n); ++p) {
            int c = cost;
            int r = rem - __builtin_popcount(p);
            if (r > n) continue;

            for (int i = 0; i < n; ++i) {
                if ((~p >> i) & 1) continue;
                for (int j = 0; j < n; ++j) c += yss[i][j];
            }

            vector<int> cs(n, 0);
            for (int j = 0; j < n; ++j) {
                for (int i = 0; i < n; ++i) {
                    if ((~p >> i) & 1) cs[j] += yss[i][j];
                }
            }
            sort(cs.begin(), cs.end());

            for (int i = 0; i < r; ++i) c += cs[i];
            ans = min(ans, c);
        }
    }

    cout << ans << "\n";
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    solve();

    return 0;
}