import java.util.Arrays;
import java.util.LinkedList;
import java.util.Scanner;

public class yukicoder123 {
    class Tuple {
        int x;
        int y;
        int[] his;

        Tuple(int x, int y, int[] his) {
            this.x = x;
            this.y = y;
            this.his = his;
        }

        boolean checkSequence(int c) {
            return isKadomatsuSequence(his[1], his[2], c);
        }

        @Override
        public String toString() {
            return "" + x + ":" + y + Arrays.toString(this.his);
        }
    }

    int[][] vec = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};

    boolean isKadomatsuSequence(int a, int b, int c) {
        if (a == c) {
            return false;
        }
        return (a - b) * (b - c) < 0;
    }

    int is(boolean b) {
        return b ? 1 : 0;
    }


    public yukicoder123() {
        Scanner scanner = new Scanner(System.in);
        int W = scanner.nextInt();
        int H = scanner.nextInt();

        int[][] matrix = new int[H][W];
        int[][][][] checked = new int[H][W][10][2];

        for (int i = 0; i < H; i++) {
            for (int j = 0; j < W; j++) {
                matrix[i][j] = scanner.nextInt();
                for (int k = 0; k < 10; k++) {
                    Arrays.fill(checked[i][j][k], Integer.MAX_VALUE);
                }

            }
        }
        LinkedList<Tuple> nextQueue = new LinkedList<>();

        LinkedList<Tuple> queue = new LinkedList<>();
        for (int i = 0; i < 10; i++) {
            Arrays.fill(checked[0][0][i], Integer.MAX_VALUE);
        }

        int start = matrix[0][0];
        if (matrix[0][0] != matrix[0][1]) {
            int flag = is(matrix[0][0] > matrix[0][1]);
            checked[0][1][start][flag] = 1;
            queue.add(new Tuple(1, 0, new int[]{0, matrix[0][0], matrix[0][1]}));
        }

        if (matrix[0][0] != matrix[1][0]) {
            int flag = is(matrix[0][0] > matrix[1][0]);
            checked[1][0][start][flag] = 1;
            queue.add(new Tuple(0, 1, new int[]{0, matrix[0][0], matrix[1][0]}));
        }


        int turn = 2;
        boolean isGoal = false;
        MAIN:
        while (queue.size() > 0) {
            while (queue.size() > 0) {
                Tuple tuple = queue.pop();
                for (int[] v : vec) {
                    int x = tuple.x + v[0];
                    int y = tuple.y + v[1];
                    if (!(0 <= x && x < W && 0 <= y && y < H)) {
                        continue;
                    }

                    if (!tuple.checkSequence(matrix[y][x])) {
                        continue;
                    }
                    int flag = is(tuple.his[2] - matrix[y][x] > 0);
                    if (checked[y][x][tuple.his[2]][flag] <= turn) {
                        continue;
                    }
                    checked[y][x][tuple.his[2]][flag] = turn;
                    if (y == H - 1 && x == W - 1) {
                        isGoal = true;
                        break MAIN;
                    }
                    nextQueue.add(new Tuple(x, y, new int[]{tuple.his[1], tuple.his[2], matrix[y][x]}));
                }
            }
            queue.addAll(nextQueue);
            nextQueue.clear();
            turn++;
        }

        if (isGoal) {
            System.out.println(turn);
        } else {
            System.out.println(-1);

        }

    }

    public static void main(String[] args) {
        yukicoder123 hoge = new yukicoder123();
    }
}