#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
#define REP(i, n) for (int i = 0; i < (n); ++i)
#define REPR(i, n) for (int i = n - 1; i >= 0; --i)
#define FOR(i, m, n) for (int i = m; i < n; ++i)
#define FORR(i, m, n) for (int i = m; i >= n; --i)
#define ALL(v) (v).begin(),(v).end()
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
const ll INF=1LL<<60;
const int inf=(1<<30)-1;
const int mod=1e9+7;
int dx[8]={1,0,-1,0,-1,-1,1,1};
int dy[8]={0,1,0,-1,-1,1,-1,1};
bool kad(int a,int b,int c){
    if(a*b*c==0) return true;
    bool u=false;
    if(a<b&&b>c&&a!=c) u=true;
    if(a>b&&b<c&&a!=c) u=true;
    return u;
}
typedef tuple<int,int,int,int,int> tp;
int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    int w,h;cin >> w >> h;
    vector<vector<int>> a(h,vector<int>(w));
    REP(i,h) REP(j,w){
        cin >> a[i][j];
    }
    vector d(h,vector(w,vector(10,vector(10,inf))));
    d[0][0][0][a[0][0]]=0;
    priority_queue<tp,vector<tp>,greater<tp>> pq;
    pq.push({0,0,0,0,a[0][0]});
    while(!pq.empty()){
        auto [u,v,W,x,y]=pq.top();
        pq.pop();
        if(u>d[v][W][x][y]) continue;
        REP(i,4){
            int X=v+dx[i],Y=W+dy[i];
            if(X<0||X>=h||Y<0||Y>=w) continue;
            if(kad(x,y,a[X][Y])){
                if(chmin(d[X][Y][y][a[X][Y]],d[v][W][x][y]+1)){
                    pq.push({d[X][Y][y][a[X][Y]],X,Y,y,a[X][Y]});
                }
            }
        }
    }
    REP(i,h) REP(j,w){

    }
    int ans=inf;
    FOR(i,1,10) FOR(j,1,10) chmin(ans,d[h-1][w-1][i][j]);
    cout << (ans==inf?-1:ans) << endl;
}