import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int h = sc.nextInt();
        int w = sc.nextInt();
        int[][] field = new int[h][w];
        for (int i = 0; i < h; i++) {
            for (int j = 0; j < w; j++) {
                field[i][j] = sc.nextInt();
            }
        }
        PriorityQueue<Path> queue = new PriorityQueue<>();
        int[][][][] costs = new int[10][10][h][w];
        for (int[][][] arr1 : costs) {
            for (int[][] arr2 : arr1) {
                for (int[] arr3 : arr2) {
                    Arrays.fill(arr3, Integer.MAX_VALUE);
                }
            }
        }
        queue.add(new Path(0, 0, 0, 0, 0));
        while (queue.size() > 0) {
            Path p = queue.poll();
            if (!isKadomatsu(p.prepre, p.pre, field[p.r][p.c]) || costs[p.prepre][p.pre][p.r][p.c] <= p.value) {
                continue;
            }
            costs[p.prepre][p.pre][p.r][p.c] = p.value;
            if (p.r > 0) {
                queue.add(new Path(p.r - 1, p.c, p.value + 1, p.pre, field[p.r][p.c]));
            }
            if (p.r < h - 1) {
                queue.add(new Path(p.r + 1, p.c, p.value + 1, p.pre, field[p.r][p.c]));
            }
            if (p.c > 0) {
                queue.add(new Path(p.r, p.c - 1, p.value + 1, p.pre, field[p.r][p.c]));
            }
            if (p.c < w - 1) {
                queue.add(new Path(p.r, p.c + 1, p.value + 1, p.pre, field[p.r][p.c]));
            }
        }
        int min = Integer.MAX_VALUE;
        for (int i = 0; i < 10; i++) {
            for (int j = 0; j < 10; j++) {
                min = Math.min(min, costs[i][j][h - 1][w - 1]);
            }
        }
        if (min == Integer.MAX_VALUE) {
            System.out.println(-1);
        } else {
            System.out.println(min);
        }
    }
    
    static boolean isKadomatsu(int prepre, int pre, int cur) {
        if (pre == 0) {
            return true;
        } else if (prepre == 0) {
            return pre != cur;
        } else {
            return prepre != cur && ((prepre < pre && pre > cur) || (prepre > pre && pre < cur));
        }
    }
    
    static class Path implements Comparable<Path> {
        int r;
        int c;
        int value;
        int prepre;
        int pre;
        
        public Path(int r, int c, int value, int prepre, int pre) {
            this.r = r;
            this.c = c;
            this.value = value;
            this.prepre = prepre;
            this.pre = pre;
        }
        
        public int compareTo(Path another) {
            return value - another.value;
        }
    }
}

class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String next() throws Exception {
        if (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}