Go: package main

import (
	"bufio"
	"container/list"
	"fmt"
	"os"
	"strconv"
	"strings"
)

func main() {
	io := NewIo()
	defer io.Flush()
	for {
		w, h := io.NextInt(), io.NextInt()
		if w == 0 {
			break
		}
		xWall := make([][]int, h)
		yWall := make([][]int, h)
		for i := 0; i < h; i++ {
			xWall[i], yWall[i] = make([]int, w), make([]int, w)
			for j := 0; j < w; j++ {
				xWall[i][j], yWall[i][j] = -1, -1
			}
		}
		for i := 0; i < h*2-1; i++ {
			if i%2 == 0 {
				for j := 0; j < w-1; j++ {
					xWall[i/2][j] = io.NextInt()
				}
			} else {
				for j := 0; j < w; j++ {
					yWall[i/2][j] = io.NextInt()
				}
			}
		}
		//io.Println(bfs(w, h, xWall, yWall))
		fmt.Println(bfs(w, h, xWall, yWall))
	}
}

type P struct {
	x, y int
}

func bfs(w, h int, x, y [][]int) int {
	d := make([][]int, h)
	for i := 0; i < h; i++ {
		d[i] = make([]int, w)
	}
	q := list.New()
	q.PushBack(P{0, 0})
	d[0][0] = 1

	for q.Len() != 0 {
		pos := q.Remove(q.Front()).(P)
		if pos.x == w-1 && pos.y == h-1 {
			break
		}
		if pos.x > 0 && x[pos.y][pos.x-1] == 0 && d[pos.y][pos.x-1] == 0 {
			d[pos.y][pos.x-1] = d[pos.y][pos.x] + 1
			q.PushBack(P{pos.x - 1, pos.y})
		}
		if pos.x < w-1 && x[pos.y][pos.x] == 0 && d[pos.y][pos.x+1] == 0 {
			d[pos.y][pos.x+1] = d[pos.y][pos.x] + 1
			q.PushBack(P{pos.x + 1, pos.y})
		}
		if pos.y > 0 && y[pos.y-1][pos.x] == 0 && d[pos.y-1][pos.x] == 0 {
			d[pos.y-1][pos.x] = d[pos.y][pos.x] + 1
			q.PushBack(P{pos.x, pos.y - 1})
		}
		if pos.y < h-1 && y[pos.y][pos.x] == 0 && d[pos.y+1][pos.x] == 0 {
			d[pos.y+1][pos.x] = d[pos.y][pos.x] + 1
			q.PushBack(P{pos.x, pos.y + 1})
		}
	}
	return d[h-1][w-1]
}

// I/O template
type Io struct {
	reader    *bufio.Reader
	writer    *bufio.Writer
	tokens    []string
	nextToken int
}

func NewIo() *Io {
	return &Io{
		reader: bufio.NewReader(os.Stdin),
		writer: bufio.NewWriter(os.Stdout),
	}
}

func (io *Io) Flush() {
	err := io.writer.Flush()
	if err != nil {
		panic(err)
	}
}

func (io *Io) NextLine() string {
	var buff []byte
	for {
		line, isPrefix, err := io.reader.ReadLine()
		if err != nil {
			panic(err)
		}
		buff = append(buff, line...)
		if !isPrefix {
			break
		}
	}
	return string(buff)
}

func (io *Io) Next() string {
	for io.nextToken >= len(io.tokens) {
		line := io.NextLine()
		io.tokens = strings.Fields(line)
		io.nextToken = 0
	}
	s := io.tokens[io.nextToken]
	io.nextToken++
	return s
}

func (io *Io) NextInt() int {
	i, err := strconv.Atoi(io.Next())
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) NextFloat() float64 {
	i, err := strconv.ParseFloat(io.Next(), 64)
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) Println(a ...interface{}) {
	fmt.Fprintln(io.writer, a...)
}

func (io *Io) Printf(format string, a ...interface{}) {
	fmt.Fprintf(io.writer, format, a...)
}

func (io *Io) PrintIntSlice(a []int) {
	b := []interface{}{}
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func (io *Io) PrintStringSlice(a []string) {
	b := []interface{}{}
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func Log(name string, value interface{}) {
	fmt.Fprintf(os.Stderr, "%s=%+v\n", name, value)
}

func ExampleIo() {
	io := NewIo()
	defer io.Flush()
	a := make([]int, 0, 3)
	a[0], a[1], a[2] = io.NextInt(), io.NextInt(), io.NextInt()
	io.Println(a)
	io.PrintIntSlice(a)
	Log("io", a)
}

C++: #include<cstdio>
#include<cstring>
#include<vector>
#include<queue>
#include<algorithm>
#include<cmath>
#include<climits>
#include<string>
#include<set>
#include<numeric>
#include<map>
#include<iostream>
using namespace std;
#define rep(i,n) for(int i = 0;i<((int)(n));i++)
#define reg(i,a,b) for(int i = ((int)(a));i<=((int)(b));i++)
#define irep(i,n) for(int i = ((int)(n)-1);i>=0;i--)
#define ireg(i,a,b) for(int i = ((int)(b));i>=((int)(a));i--)
typedef long long ll;
typedef pair<ll, ll> mp;


int w,h,field[30][30],visited[30][30],wall[61][30],ans;
queue<int> Q;

//queue??§?????????????????????visited?????????
//??¨??????field=min(field,field[x][y]+1)
//??¨??????visited??§???????????°queue?????\?????????

//field[y][x]

int main(void){
	while(1){
		ans=0;
		cin>>w>>h;
		if(w==0 && h==0)break;
		rep(i,h){
			rep(j,w){
				field[i][j]=100000;//?????¢????????????
				visited[i][j]=0;//?¨????????????????
			}
		}
		rep(i,h*2-1){
			if(i%2==0){
				rep(j,w-1)cin>>wall[i][j];
			}else if(i%2==1){
				rep(j,w)cin>>wall[i][j];
			}
		}

		//(0,0)???queue?????????
		//??????????°?????????????queue?????????????????\???????????????????????????????????????
		Q.push(0);
		Q.push(0);
		field[0][0]=1;

		while(!Q.empty()){
			int x = Q.front();
			Q.pop();
			int y = Q.front();
			Q.pop();
			visited[y][x]=1;
			//???????????????????????????????????????
			if(x>0 && wall[2*y][x-1]==0){//???
				if(visited[y][x-1]==0){
					Q.push(x-1);
					Q.push(y);
				}
				if(field[y][x-1]>field[y][x]+1)field[y][x-1]=field[y][x]+1;
			}
			if(x<w-1 && wall[2*y][x]==0){//???
				if(visited[y][x+1]==0){
					Q.push(x+1);
					Q.push(y);
				}
				if(field[y][x+1]>field[y][x]+1)field[y][x+1]=field[y][x]+1;
			}
			if(y>0 && wall[2*y-1][x]==0){//???
				if(visited[y-1][x]==0){
					Q.push(x);
					Q.push(y-1);
				}
				if(field[y-1][x]>field[y][x]+1)field[y-1][x]=field[y][x]+1;
			}
			if(y<h-1 && wall[2*y+1][x]==0){//???
				if(visited[y+1][x]==0){
					Q.push(x);
					Q.push(y+1);
				}
				if(field[y+1][x]>field[y][x]+1)field[y+1][x]=field[y][x]+1;
			}
		}
		if(visited[h-1][w-1]==1){
			cout<<field[h-1][w-1]<<endl;
		}else{
			cout<<0<<endl;
		}
	}
	return 0;
}

C++: #include<stdio.h>
#include<iostream>
#include<math.h>
#include<algorithm>
#include<string>
#define pi 3.14159
#define Inf 9999
using namespace std;



int w, h, a[59][59];
void dfs(int y, int x, int step);
int main(){
	while(1) {
		cin >> w >> h;
		if(w == 0 && h == 0) break;
		for(int i = 0; i < 2*h-1; i++) {
			for(int j = 0; j < 2*w-1; j++) {
				if(i % 2 == 0 && j % 2 == 0) a[i][j] = Inf;
				else if(i % 2 == 1 && j % 2 == 1) a[i][j] = Inf;
				else cin >> a[i][j];
			}
		}
		a[0][0] = 1;
		if(a[1][0] == 0) dfs(2, 0, 1);
		if(a[0][1] == 0) dfs(0, 2, 1);
		if(a[2*h-2][2*w-2] == Inf) cout << 0 <<endl;
		else cout << a[2*h-2][2*w-2] <<endl;
	}
	return 0;
}

void dfs(int y, int x, int step) {
	if(y < 0 || x < 0 || y >= 2*h-1 || x >= 2*w-1) return;
	if(step >= a[y][x]) return;
	else {
		step++;
		a[y][x] = step;
		if(y == 2*h-2 && x == 2*w-2) return;
		if(y+1 < 2*h-1) { 
			if(a[y+1][x] == 0) dfs(y+2, x, step);
		}
		if(x + 1 < 2*w-1) {
			if(a[y][x+1] == 0) dfs(y, x+2, step);
		}
		if(y - 1 >= 0) {
			if(a[y-1][x] == 0) dfs(y-2, x, step);
		}
		if(x - 1 >= 0) {
			if(a[y][x-1] == 0) dfs(y, x-2, step);
		}
	}
	return;
}

C++: #include<bits/stdc++.h>
using namespace std;

int W,H;
int fie[111][111];
int D[111][111];
int dx[]={0,1,0,-1};
int dy[]={1,0,-1,0};
struct state { 
  int x,y,c;
};

bool check(int x,int y){
  if( x < 0 || y < 0 || x >= 2*W || y >= 2*H ) return true;
  return false;
}

int bfs(){
  memset(D,0,sizeof(D));
  queue<state> q;
  q.push( (state){0,0,1} );
  D[0][0] = 1;
  while( !q.empty() ){
    state p = q.front(); q.pop();
    //    cout << p.x << " " << p.y << " " << p.c << endl;
    if( p.x == (W-1)*2 && p.y == (H-1)*2 ) return p.c;
    for(int i=0;i<4;i++){
      int ncx = p.x + dx[i], ncy = p.y + dy[i];
      int nx = p.x + dx[i]*2, ny = p.y + dy[i]*2;
      if( check(nx,ny) ) continue;
      if( fie[ncx][ncy]  ) continue;
      if( D[nx][ny] == 0 ){
	D[nx][ny] = p.c + 1;
	q.push( (state){nx,ny,p.c+1} );
      }
    }
  }
  return 0;
}

int main(){
  while( cin >> W >> H && (W||H) ){
    memset(fie,0,sizeof(fie));
    for(int i=0;i<2*H-1;i++){
      for(int j=0;j<W-(i%2==0?1:0);j++){
	if( i & 1 )
	  cin >> fie[2*j][i];
	else
	  cin >> fie[2*j+1][i];
      }
    }

    cout << bfs() << endl;
  }
}