#include <bits/stdc++.h>

using namespace std;

#define N 110
#define pb push_back

int in[N][N];

vector<int> e[N * N];
vector<int> e2[N * N];

bool vis[N * N];

int dist1[N * N];
int dist2[N * N];
int dist3[N * N];

int main()
{
    int h, w;
    scanf("%d%d", &h, &w);
    for (int i = 0; i < h; i++)
    {
        for (int j = 0; j < w; j++)
        {
            scanf("%d", &in[i][j]);
        }
    }
    for (int j = 0; j < w; j++)
        in[h][j] = 0;

    int id1 = in[0][0], id2 = in[0][0];

    for (int j = 0; j < w; j++)
        if (in[0][j] != id2)
        {
            id2 = in[0][j];
            break;
        }

    for (int i = 0; i < h; i++)
    {
        for (int j = 0; j < w; j++)
        {
            if (in[i][j] != in[i + 1][j])
            {
                e[in[i][j]].pb(in[i + 1][j]);
                e2[in[i + 1][j]].pb(in[i][j]);
            }
        }
    }

    for (int i = 0; i < N * N; i++)
    {
        dist1[i] = N;
        dist2[i] = N;
        dist3[i] = N;
    }

    queue<int> q;
    q.push(id1);
    dist1[id1] = 1;
    vis[id1] = 1;
    while (q.size())
    {
        int x = q.front();
        q.pop();

        for (int i = 0; i < e[x].size(); i++)
        {
            if (!vis[e[x][i]])
            {
                q.push(e[x][i]);
                dist1[e[x][i]] = dist1[x] + 1;
                vis[e[x][i]] = 1;
            }
        }
    }
    memset(vis, 0, sizeof vis);

    q.push(id2);
    dist2[id2] = 1;
    vis[id2] = 1;
    while (q.size())
    {
        int x = q.front();
        q.pop();

        for (int i = 0; i < e[x].size(); i++)
        {
            if (!vis[e[x][i]])
            {
                q.push(e[x][i]);
                dist2[e[x][i]] = dist2[x] + 1;
                vis[e[x][i]] = 1;
            }
        }
    }
    memset(vis, 0, sizeof vis);

    q.push(0);
    dist3[0] = 1;
    vis[0] = 1;
    while (q.size())
    {
        int x = q.front();
        q.pop();

        for (int i = 0; i < e2[x].size(); i++)
        {
            if (!vis[e2[x][i]])
            {
                q.push(e2[x][i]);
                dist3[e2[x][i]] = dist3[x] + 1;
                vis[e2[x][i]] = 1;
            }
        }
    }

    // for (int i = 0; i < 14; i++)
    // {
    //     printf("%d ", dist1[i]);
    // }
    // puts("");

    // for (int i = 0; i < 14; i++)
    // {
    //     printf("%d ", dist2[i]);
    // }
    // puts("");

    // for (int i = 0; i < 14; i++)
    // {
    //     printf("%d ", dist3[i]);
    // }
    // puts("");

    int ans = 3 * N;
    for (int i = 0; i < N * N; i++)
    {
        ans = min(ans, dist1[i] + dist2[i] + dist3[i] - 3);
    }
    printf("%d\n", ans);

    return 0;
}