#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
using namespace std;

int dy[] = {-1, 1, 0, 0};
int dx[] = {0, 0, 1, -1};

int main()
{
    int w, h;
    cin >> w >> h;

    vector<vector<int> > m(h+2, vector<int>(w+2, -1));
    for(int y=1; y<=h; ++y){
        for(int x=1; x<=w; ++x){
            cin >> m[y][x];
        }
    }

    vector<vector<vector<vector<bool> > > > check(h+2, vector<vector<vector<bool> > >(w+2, vector<vector<bool> >(10, vector<bool>(10, false))));
    queue<tuple<int, int, int, int> > q;
    check[1][1][0][m[1][1]] = 1;
    q.push(make_tuple(1, 1, 0, m[1][1]));

    int ret = 0;
    while(!q.empty()){
        int n = q.size();
        while(--n >= 0){
            int y, x, a, b;
            tie(y, x, a, b) = q.front();
            q.pop();
            if(y == h && x == w){
                cout << ret << endl;
                return 0;
            }

            for(int i=0; i<4; ++i){
                int y2 = y + dy[i];
                int x2 = x + dx[i];
                int c = m[y2][x2];
                if(c == -1)
                    continue;
                if(a != 0 && !(a != c && ((a < b && b > c) || (a > b && b < c))))
                    continue;

                if(!check[y2][x2][b][c]){
                    check[y2][x2][b][c] = true;
                    q.push(make_tuple(y2,x2, b, c));
                }
            }
        }
        ++ ret;
    }

    cout << -1 << endl;
    return 0;
}