#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <cmath>
#include <stdio.h>
#include <queue>
#include <deque>
#include <cstdio>
#include <set>
#include <map>
#include <bitset>
#include <stack>
#include <cctype>
using namespace std;
int a[20][20];
int s[40];
int main() {
    int n, m;
    cin >> n >> m;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            cin >> a[i][j];
        }
    }
    for (int i = 0; i < n; i++) {
        s[2 * n] += a[i][i];
        s[2 * n + 1] += a[i][n - i - 1];
        for (int j = 0; j < n; j++) {
            s[i] += a[i][j];
        }
    }
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            s[n + i] += a[j][i];
        }
    }
    int ans = 0;
    for (int i = 0; i < m; i++) {
        int ans1 = 1000000007, n1;
        for (int j = 0; j < 2 * n + 2; j++) {
            if (ans1 > s[j]) {
                ans1 = s[j];
                n1 = j;
            }
        }
        if (n1 == 2 * n + 1) {
            for (int j = 0; j < n; j++) {
                s[j] -= a[j][n - j - 1];
                s[2 * n - j - 1] -= a[j][n - j - 1];
            }
        }
        else if (n1 == 2 * n) {
            for (int j = 0; j < n; j++) {
                s[j] -= a[j][j];
                s[n + j] -= a[j][j];
            }
        }
        else if (n1 >= n) {
            for (int j = 0; j < n; j++) {
                s[j] -= a[j][n1 - n];
            }
        }
        else {
            for (int j = 0; j < n; j++) {
                s[n + j] -= a[n1 - n][j];
            }
        }
        s[n1] = 1000000007;
        ans += ans1;
    }
    cout << ans << endl;
}