#define _CRT_SECURE_NO_WARNINGS
#include <deque>
#include <map>
#include <queue>
#include <iostream>
#include <cstdio>
#include <cstring>
#include <ctime>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <sstream>
#include <utility>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> pii;
#define all(c) (c).begin(), (c).end()
#define loop(i,a,b) for(ll i=a; i<ll(b); i++)
#define rep(i,b) loop(i,0,b)
#define each(e,c) for(auto&e:c)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define mt make_tuple
#define lb lower_bound
#define ub upper_bound
#ifdef DEBUG
#define dump(...) (cerr<<#__VA_ARGS__<<" = "<<(DUMP(),__VA_ARGS__).str()<<" ["<<__LINE__<<"]"<<endl)
struct DUMP:ostringstream{template<class T>DUMP &operator,(const T&t){if(this->tellp())*this<<", ";*this<<t;return *this;}};
#else
#define dump(...)
#endif
template<class T> ostream& operator<<(ostream& os, vector<T> const& v){
    rep(i,v.size()) os << v[i] << (i+1==v.size()?"":" ");
    return os;
}

int W,H;
int M[111][111];

// d,v,pre
typedef tuple<int,int,int> State;
typedef tuple<int,int> ns;
map<ns,int> dp;

int solve(){
    dp.clear();
    dp[mt(0,-1)] = 0;
    priority_queue<State> q;
    q.emplace(0,0,-1);
    while(q.size()){
        int d,v,p;
        tie(d,v,p) = q.top(); q.pop();
        d = -d;
        if(v==W*H-1) return d;
        int dx[]={0,1,-1,0}, dy[]={1,0,0,-1};
        if(dp.count(tie(v,p)) && dp[tie(v,p)] < d) continue;
        rep(i,4){
            int nx = v%W+dx[i], ny = v/W+dy[i];
            int x = v%W, y = v/W;
            int px = p%W, py = p/W;
            if(nx < 0 || nx >= W || ny < 0 || ny >= H) continue;
            if(p==-1){
                if(M[y][x]==M[ny][nx]){
                    continue;
                }
            } else {
                if(M[py][px] == M[ny][nx]) continue;
                if(!((M[py][px] < M[y][x] && M[y][x] > M[ny][nx]) ||
                     (M[py][px] > M[y][x] && M[y][x] < M[ny][nx]))){
                    continue;
                }
            }
            int nv = ny*W+nx;
            if(dp.count(tie(nv,v))==0 || dp[tie(nv,v)] > d+1){
                dp[tie(nv,v)] = d+1;
                q.emplace(-(d+1),nv,v);
            }
        }
    }
    return -1;
}

int main(){
    while(cin>>W>>H && W){
        rep(i,H)rep(j,W) cin >> M[i][j];
        cout << solve() << endl;
    }
}