#include <iostream>
#include <cmath>
#include <cctype>
#include <vector>
#include <algorithm>
#include <set>
#include <map>
#include <deque>
#include <stack>
#include <unordered_set>
#include <sstream>
#include <cstring>
#include <iomanip>
#include <queue>
#include <unordered_map>
#include <random>
#include <cfloat>
#include <chrono>
#include <bitset>
#include <complex>
#include <immintrin.h>
#include <cassert>
int32_t ans = 100'500;
void solve2(int32_t ind, int32_t n, int32_t m, int32_t ans_cur, int32_t** arr) {
if(ind == n) {
bool ok = true;
for(int32_t i = 0; i < n; i++) {
for(int32_t j = 0; j < m; j++)
if(arr[i][j] != arr[i][0])
ok = false;
}
bool ok2 = true;
for(int32_t i = 0; i < n; i++) {
for(int32_t j = 0; j < m; j++)
if(arr[i][j] != arr[0][j])
ok2 = false;
}
if(ok || ok2)
ans = std::min(ans, ans_cur);
return;
}
for(int32_t i = 0; i < m; i++) {
solve2(ind + 1, n, m, ans_cur + std::min(i, m - i), arr);
int32_t last = arr[ind][0];
for(int32_t j = 0; j < m - 1; j++)
arr[ind][j] = arr[ind][j + 1];
arr[ind][m - 1] = last;
}
}
void solve1(int32_t ind, int32_t m, int32_t n, int32_t ans_cur, int32_t** arr) {
if(ind == m) {
solve2(0, n, m, ans_cur, arr);
return;
}
for(int32_t i = 0; i < n; i++) {
solve1(ind + 1, m, n, ans_cur + std::min(i, n - i), arr);
int32_t last = arr[0][ind];
for(int32_t j = 0; j < n - 1; j++)
arr[j][ind] = arr[j + 1][ind];
arr[n - 1][ind] = last;
}
}
int main() {
int32_t n, m;
std::cin >> n >> m;
int32_t** arr = new int32_t*[n];
for(int32_t i = 0; i < n; i++) {
arr[i] = new int32_t[m];
for(int32_t j = 0; j < m; j++)
std::cin >> arr[i][j];
//arr[i][j] = 1;
}
solve1(0, m, n, 0, arr);
std::cout << ans;
return 0;
}
