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

public class Main {

	public static final int[][] move_dir = {{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
	
	public static boolean is_valid(int x, int y, int W, int H){
		return x >= 0 && x < W && y >= 0 && y < H;
	}
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		final int W = sc.nextInt();
		final int H = sc.nextInt();
		int[][] heights = new int[H][W];
		for(int i = 0; i < H; i++){
			for(int j = 0; j < W; j++){
				heights[i][j] = sc.nextInt();
			}
		}
		
		LinkedList<Integer> x_queue = new LinkedList<Integer>();
		LinkedList<Integer> y_queue = new LinkedList<Integer>();
		LinkedList<Integer> prev_queue = new LinkedList<Integer>();
		
		
		int[][][] minimum_cost = new int[10][H][W];
		for(int i = 0; i < 10; i++){
			for(int j = 0; j < H; j++){
				for(int k = 0; k < W; k++){
					minimum_cost[i][j][k] = Integer.MAX_VALUE;
				}
			}
		}
		minimum_cost[0][0][0] = 0;
		x_queue.add(0);
		y_queue.add(0);
		prev_queue.add(0);
		
		while(!x_queue.isEmpty()){
			final int x = x_queue.poll();
			final int y = y_queue.poll();
			
			final int curr = heights[y][x];
			final int prev = prev_queue.poll();
			
			if(curr == prev){
				continue;
			}else if(x == W - 1 && y == H - 1 && prev > 0){
				System.out.println(minimum_cost[prev][y][x]);
				return;
			}
			
			//System.out.println(x + " " + y + " " + prev + " " + minimum_cost[prev][y][x]);
			
			for(final int[] move : move_dir){
				final int nx = x + move[0];
				final int ny = y + move[1];
				
				if(!is_valid(nx, ny, W, H)){
					continue;
				}
				
				final int next = heights[ny][nx];
				if(prev == next){
					continue;
				}
				
				final int next_cost = minimum_cost[prev][y][x] + 1;
				if(prev == 0 || prev < curr && curr > next || prev > curr && curr < next){
					if(minimum_cost[curr][ny][nx] > next_cost){
						minimum_cost[curr][ny][nx] = next_cost;
						x_queue.add(nx);
						y_queue.add(ny);
						prev_queue.add(curr);
					}
				}
				
			}
			
		}
		
		System.out.println(-1);
		
		
	}

}