#include <bits/stdc++.h>
using namespace std;

int minimumRoom(int N,int M,vector<vector<int>> &A){

    vector<vector<int>> dist(N,vector<int>(M,10000000));
    vector<vector<bool>> visited(N,vector<bool>(M,false));

    queue<pair<int,int>> q;
    q.push({0,0});
    dist[0][0] = 1;
    visited[0][0] = true;

    while(!q.empty()){
        auto curr = q.front();
        q.pop();

        int i = curr.first;
        int j = curr.second;

        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;
            q.push({i+1,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;
            q.push({i,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;
            q.push({i-1,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;
            q.push({i,j-1});
        }
    }

    if(visited[N-1][M-1]){
        return dist[N-1][M-1];
    }

    return -1;
}

int main()
{
    int N,M;
    cin>>N>>M;

    vector<vector<int>> A(N,vector<int>(M));

    for(int i=0;i<N;i++){
        for(int j=0;j<M;j++){
            cin>>A[i][j];
        }
    }

    cout<<minimumRoom(N,M,A)<<endl;
}