import java.util.*;

public class Solution {

    static Scanner sc = new Scanner(System.in);


    public static int minimumRoom(int N,int M,int[][] A){

        int[][] dist = new int[N][M];
        boolean[][] visited = new boolean[N][M];

        for(int i=0;i<N;i++){
            for(int j=0;j<M;j++){
                dist[i][j] = 10000000;
                visited[i][j] = false;
            }
        }

         Queue<Integer> qx=new LinkedList<>();
         Queue<Integer> qy=new LinkedList<>();

         qx.add(0);
         qy.add(0);

         dist[0][0] = 1;
         visited[0][0] = true;

         while(!qx.isEmpty()) {
             int i = qx.remove();
             int j = qy.remove();

             if(i+1<N && visited[i+1][j] == false && A[i+1][j]!=A[i][j]){
                 dist[i+1][j] = dist[i][j]+1;
                 visited[i+1][j] = true;
                 qx.add(i+1);
                 qy.add(j);
             }
             if(j+1<M && visited[i][j+1] == false && A[i][j+1]!=A[i][j]){
                 dist[i][j+1] = dist[i][j]+1;
                 visited[i][j+1] = true;
                 qx.add(i);
                 qy.add(j+1);
             }
             if(i-1>=0 && visited[i-1][j] == false && A[i-1][j]!=A[i][j]){
                 dist[i-1][j] = dist[i][j]+1;
                 visited[i-1][j] = true;
                 qx.add(i-1);
                 qy.add(j);
             }
             if(j-1>=0 && visited[i][j-1] == false && A[i][j-1]!=A[i][j]){
                 dist[i][j-1] = dist[i][j]+1;
                 visited[i][j-1] = true;
                 qx.add(i);
                 qy.add(j-1);
             }
         }
         if(visited[N-1][M-1]) {
             return dist[N-1][M-1];
         }
         return -1;
    }

    public static void main(String[] args) {
        int N,M;
        N = sc.nextInt();
        M = sc.nextInt();

        int[][] A = new int[N][M];

        for(int i=0;i<N;i++){
            for(int j=0;j<M;j++){
                A[i][j] = sc.nextInt();
            }
        }

        System.out.println(minimumRoom(N,M,A));
    }
}