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 <bits/stdc++.h>
using namespace std;

int w, h;
vector<vector<int>> dist;
struct Wall
{
  bool upper, lower, left, right;
};
vector<vector<Wall>> wall;

void init()
{
  dist.resize(h, vector<int>(w));
  wall.resize(h, vector<Wall>(w));
  dist.assign(h, vector<int>(w, 0));
  wall.assign(h, vector<Wall>(w, Wall{false, false, false, false}));
}

void input()
{
  int c;
  for (int i = 0; i < 2 * h - 1; i++)
  {
    if (i % 2 == 0)
    {
      for (int j = 0; j < w - 1; j++)
      {
        cin >> c;
        wall.at(i / 2).at(j).right = bool(c);
        wall.at(i / 2).at(j + 1).left = bool(c);
      }
    }
    else
    {
      for (int j = 0; j < w; j++)
      {
        cin >> c;
        wall.at(i / 2).at(j).lower = bool(c);
        wall.at((i / 2) + 1).at(j).upper = bool(c);
      }
    }
  }
  for (int i = 0; i < h; i++)
  {
    wall.at(i).at(0).left = true;
    wall.at(i).at(w - 1).right = true;
  }
  for (int j = 0; j < w; j++)
  {
    wall.at(0).at(j).upper = true;
    wall.at(h - 1).at(j).lower = true;
  }
}

int dfs()
{
  queue<pair<int, int>> que;
  dist.at(0).at(0) = 1;
  que.push(make_pair(0, 0));
  int cur_y, cur_x;
  while (!que.empty())
  {
    tie(cur_y, cur_x) = que.front();
    que.pop();
    int ny, nx;
    ny = cur_y - 1;
    nx = cur_x;
    if (0 <= ny && ny < h && 0 <= nx && nx < w)
    {
      if (!wall.at(cur_y).at(cur_x).upper)
      {
        if (dist.at(ny).at(nx) == 0)
        {
          dist.at(ny).at(nx) = dist.at(cur_y).at(cur_x) + 1;
          que.push(make_pair(ny, nx));
        }
      }
    }
    ny = cur_y + 1;
    nx = cur_x;
    if (0 <= ny && ny < h && 0 <= nx && nx < w)
    {
      if (!wall.at(cur_y).at(cur_x).lower)
      {
        if (dist.at(ny).at(nx) == 0)
        {
          dist.at(ny).at(nx) = dist.at(cur_y).at(cur_x) + 1;
          que.push(make_pair(ny, nx));
        }
      }
    }
    ny = cur_y;
    nx = cur_x - 1;
    if (0 <= ny && ny < h && 0 <= nx && nx < w)
    {
      if (!wall.at(cur_y).at(cur_x).left)
      {
        if (dist.at(ny).at(nx) == 0)
        {
          dist.at(ny).at(nx) = dist.at(cur_y).at(cur_x) + 1;
          que.push(make_pair(ny, nx));
        }
      }
    }
    ny = cur_y;
    nx = cur_x + 1;
    if (0 <= ny && ny < h && 0 <= nx && nx < w)
    {
      if (!wall.at(cur_y).at(cur_x).right)
      {
        if (dist.at(ny).at(nx) == 0)
        {
          dist.at(ny).at(nx) = dist.at(cur_y).at(cur_x) + 1;
          que.push(make_pair(ny, nx));
        }
      }
    }
  }
  return dist.at(h - 1).at(w - 1);
}

int main()
{
  vector<int> ans;
  while (1)
  {
    cin >> w >> h;
    if (w == 0 && h == 0)
    {
      break;
    }
    init();
    input();
    ans.push_back(dfs());
  }
  for (int i = 0; i < ans.size(); i++)
  {
    cout << ans.at(i) << endl;
  }
}

C++: #include<iostream>
#include<queue>
#define INF 1e9
using namespace std;

int dx[4]={0,0,1,-1};
int dy[4]={1,-1,0,0};
int maze[60][60];
int d[60][60];

typedef pair<int,int>P;

int bfs(int w,int h){
  
  queue<P> Q;
  
  P start;
  start.first=1;start.second=1;
  Q.push(start);
  
  for(int i=1 ; i < h*2 ; i++){
    for(int j=1 ; j < w*2 ; j++){
      d[i][j]=INF;
    }
  }
  d[1][1]=1;
  
  while(!Q.empty()){
    P temp;
    temp=Q.front();
    Q.pop();
    int x=temp.first;
    int y=temp.second;
    if(x==w*2-1 && y==h*2-1)break;
    for(int i=0 ; i < 4 ; i++){
      int nx=x+2*dx[i];
      int ny=y+2*dy[i];
      int wx=x+dx[i];
      int wy=y+dy[i];
      if(nx > 0 && ny > 0 && nx < w*2 && ny < h*2){
	if(maze[wy][wx] == 0 && d[ny][nx] == INF){
	  d[ny][nx]=d[y][x]+1;
	  P temp2;
	  temp2.first=nx;
	  temp2.second=ny;
	  Q.push(temp2);
	}
      } 
    }
  }
  
  return d[h*2-1][w*2-1];
}
int main(){
  
  int w,h;

  while(1){
    
    cin >>w>>h;
    if(w==0 && h==0)break;

    for(int i=1 ; i < h*2 ; i++){
      if(i%2){
	for(int j=2 ; j < w*2 ; j+=2){
	  cin >>maze[i][j];
	}
      }else{
	for(int j=1 ; j < w*2 ; j+=2){
	  cin >>maze[i][j];
	}
      }
    }

    int min=bfs(w,h);
    if(min == INF){
      cout <<"0"<<endl;
    }else{
      cout <<min<<endl;
    }

  } 
  return 0;
}