#include <algorithm>
#include <complex>
#include <cstdlib>
#include <ctime>
#include <iomanip>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>

using namespace std;
#define SAY_YES cout << "YES" << endl;
#define SAY_Yes cout << "Yes" << endl;
#define SAY_NO cout << "NO" << endl;
#define SAY_No cout << "No" << endl;
#define IFYES(TRUE_OR_FALSE)   \
    if (TRUE_OR_FALSE)         \
    {                          \
        cout << "YES" << endl; \
    }                          \
    else                       \
    {                          \
        cout << "NO" << endl;  \
    }
#define IFYes(TRUE_OR_FALSE)   \
    if (TRUE_OR_FALSE)         \
    {                          \
        cout << "Yes" << endl; \
    }                          \
    else                       \
    {                          \
        cout << "No" << endl;  \
    }
#define IFyes(TRUE_OR_FALSE)   \
    if (TRUE_OR_FALSE)         \
    {                          \
        cout << "yes" << endl; \
    }                          \
    else                       \
    {                          \
        cout << "no" << endl;  \
    }
#define DEBUG_OUTPUT_ARRAY(XXX, ONE)                            \
    for (int i = 0; i < (ONE); i++)                             \
    {                                                           \
        cout << "DEBUG: i = " << i << " -> " << XXX[i] << endl; \
    }
#define DEBUG_OUTPUT_ARRAY2(XXX, ONE, TWO)                             \
    for (int i = 0; i < (ONE); i++)                                    \
    {                                                                  \
        cout << "<<< i = " << i << " >>>" << endl;                     \
        for (int j = 0; j < (TWO); j++)                                \
        {                                                              \
            cout << "DEBUG: j = " << j << " -> " << XXX[i][j] << endl; \
        }                                                              \
    }
#define DEBUG_OUTPUT_ARRAY2_BOX(XXX, ONE, TWO) \
    for (int i = 0; i < (ONE); i++)            \
    {                                          \
        cout << i << "  ";                     \
        for (int j = 0; j < (TWO); j++)        \
        {                                      \
            cout << XXX[i][j] << " ";          \
        }                                      \
        cout << endl;                          \
    }

typedef pair<long long int, long long int> pll;


const long long int mod = 1000000007;
const long long int INF = 99999999999999999;

long long int R,C,sy,sx,gy,gx;

queue<pll>que;
int main()
{
    cout << fixed << setprecision(18);
	cin>>C>>R;
    while(C!=0||R!=0){
        
        long long int used[255][255]={},res[255][255]={},tmp;
        long long int c[255][255]={};
        for(long long int i = 0; i < 2*R; i++){
            for(long long int j = 0; j < 2*C; j++){
                res[i][j]=INF;
            }
        }
        for(int i=1;i<=2*R-1;i++){
            if(i%2==1){
                for(long long int j = 1; j <= C-1; j++){
                    cin>>tmp;
                    c[i][2*j]=tmp;
                }
            }else{
                for(long long int j = 1; j <= C; j++){
                    cin>>tmp;
                    c[i][2*j-1]=tmp;
                }
            }
            
        }
        for(long long int i = 0; i  <=2* C; i  ++){
            c[0][i]=1;
            c[2*R][i]=1;
        }
        for(long long int i = 0; i  <=2* R; i  ++){
            c[i][0]=1;
            c[i][2*C]=1;
        }

        for(long long int i = 2; i < 2*R; i+=2){
            for(long long int j = 2; j < 2*C; j+=2){
                c[i][j]=1;
                
            }
        }
        que.push({1,1});
        res[1][1]=1;
        while(!que.empty()){
            if(c[que.front().first][que.front().second]==1||used[que.front().first][que.front().second]){
                que.pop();
                continue;
            }
            if((que.front().first%2==0) ^ (que.front().second%2==0)){
                res[que.front().first][que.front().second]--;
            }
            used[que.front().first][que.front().second]=true;
            //cout<<1;
            /*
            used[que.front().first+1][que.front().second]=true;
            used[que.front().first-1][que.front().second]=true;
            used[que.front().first][que.front().second+1]=true;
            used[que.front().first][que.front().second-1]=true;
            */
            que.push({que.front().first+1,que.front().second});
            que.push({que.front().first-1,que.front().second});
            que.push({que.front().first,que.front().second+1});
            que.push({que.front().first,que.front().second-1});
            
            
            res[que.front().first+1][que.front().second]=min(res[que.front().first+1][que.front().second],res[que.front().first][que.front().second]+1);
            res[que.front().first-1][que.front().second]=min(res[que.front().first-1][que.front().second],res[que.front().first][que.front().second]+1);
            res[que.front().first][que.front().second+1]=min(res[que.front().first][que.front().second+1],res[que.front().first][que.front().second]+1);
            res[que.front().first][que.front().second-1]=min(res[que.front().first][que.front().second-1],res[que.front().first][que.front().second]+1);
        }
        if(res[2*R-1][2*C-1]==INF){res[2*R-1][2*C-1]=0;}
        cout<<res[2*R-1][2*C-1]<<endl;
        //DEBUG_OUTPUT_ARRAY2_BOX(c,2*R,2*C);
        cin>>C>>R;
    }
}




Measured memory_bytes: 4624