883

#include <iostream>
#include <fstream>
using namespace std;

ifstream fin("traversare.in");
ofstream fout("traversare.out");

int n , m, nrI, nrP;
int  a[1002][1002];
short x[1000005], y[1000005];

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

int main(){
    fin >> n >> m;
    for(int i = 1 ; i <= n ; i ++)
        for(int j = 1 ; j <= m ; j ++)
            fin >> a[i][j];
    //facem obstacolele -1
    for(int i = 1 ; i <= n ; i ++)
        for(int j = 1 ; j <= m ; j ++)
            a[i][j] = - a[i][j];
    int st = 1 , dr = 0;
    for(int j =1 ; j <= m ; j ++)
        if(a[1][j] == 0)
        {
            dr ++;
            x[dr] = 1 , y[dr] = j;
            a[1][j] = 1;
        }
    while(st <= dr)
    {
        int i = x[st] , j = y[st];
        for(int k = 0 ; k < 4 ; k ++)
        {
            int ii = i + dx[k] , jj = j + dy[k];
            if(ii > 0 && ii <= n && jj > 0 && jj <= m && a[ii][jj] == 0)
            {
                dr ++;
                x[dr] = ii, y[dr] = jj;
                a[ii][jj] = a[i][j]  + 1;
            }
        }
        st ++;
    }

    int mmin = 1000005;
    for(int j = 1 ; j <= m ; j ++)
        if(a[n][j] > 0)
            if(a[n][j] < mmin)
                mmin = a[n][j];

    fout << mmin << "\n";

    return 0;
}