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<algorithm>
#include<bitset>
#include<iostream>
#include<iomanip>
#include<set>
#include<string>
#include<math.h>
#include<string>
#include<queue>
#include<vector>
using namespace std;
typedef long long int ll;
typedef pair<int, ll> P;

//--------------
//#define DEBUG
//--------------

#ifdef DEBUG
	#define debugprint(x) cout<<x<<" "
	#define debugendl cout<<endl
	#define debug(x) x
#else
	#define debugprint(x)
	#define debugendl
	#define debug(x)
#endif

class zahyo{
	public:
	int x;
	int y;
	zahyo(){
		x=0;
		y=0;
	}
	zahyo(int x_,int y_){
		x=x_;
		y=y_;
	}
	void print(){
		cout<<x<<" "<<y;
	}
	zahyo operator+(zahyo add){
		add.x=this->x+add.x;
		add.y=this->y+add.y;
		return add;
	}
	zahyo operator-(zahyo add){
		add.x=this->x-add.x;
		add.y=this->y-add.y;
		return add;
	}
	zahyo operator*(int t){
		zahyo temp;
		temp.x=this->x*t;
		temp.y=this->y*t;
		return temp;
	}
	zahyo operator%(int t){
		zahyo temp(this->x%t,this->y%t);
		return temp;
	}
	zahyo operator/(int t){
		zahyo temp(this->x/t,this->y/t);
		return temp;
	}
	bool operator==(const zahyo add) const{
		if(add.x==this->x and add.y==this->y){return true;}
		else{return false;}
	}
	bool operator!=(const zahyo add) const{
		if(add.x==this->x or add.y==this->y){return false;}
		else{return true;}
	}
	bool operator<(const zahyo add) const{
		if(this->x<add.x){return true;}
		else if(this->x==add.x and this->y<add.y){return true;}
		else{return false;}
	}
	bool operator>(const zahyo add) const{
		if(this->x>add.x){return true;}
		else if(this->x==add.x and this->y>add.y){return true;}
		else{return false;}
	}
	void input(){
		cin>>x>>y;
	}
};

zahyo ways[4];



int main(){
	ways[0].x=1;
	ways[1].x=-1;
	ways[2].y=1;
	ways[3].y=-1;
	int c,r;
	while(1){
		cin>>r>>c;
		if(c==0 and r==0){break;}
		int conect[50][50][4]={};
		int arrived[50][50]={};
		for(int i=0;i<c;i++){
			for(int j=0;j<r-1;j++){
				int temp;
				cin>>temp;
				if(temp==0){
					conect[i][j][2]=1;
					conect[i][j+1][3]=1;
				}
			}
			if(i!=c-1){
				for(int j=0;j<r;j++){
					int temp;
					cin>>temp;
					if(temp==0){
						conect[i][j][0]=1;
						conect[i+1][j][1]=1;
					}
				}
			}
		}
		int ans=1;
		queue<zahyo> widesearch;
		zahyo start(0,0);
		zahyo goal(c-1,r-1);
		bool ungoaled=true;
		arrived[0][0]=1;
		widesearch.push(start);
		while(widesearch.size()>0){
			if(ungoaled==false){break;}
			ans++;
			int size=widesearch.size();
			for(int i=0;i<size;i++){
				zahyo temp=widesearch.front();
				debug(temp.print());
				debug(cout<<",";)
				widesearch.pop();
				for(int j=0;j<4;j++){
					zahyo now=temp+(ways[j]*conect[temp.x][temp.y][j]);
					if(now==goal){
						ungoaled=false;
					}
					if(now.x>=0 and now.x<c and now.y>=0 and now.y<r){
						if(arrived[now.x][now.y]==0){
							arrived[now.x][now.y]=1;
							widesearch.push(now);
						}
					}
				}
			}
			debugendl;
		}
		if(ungoaled){
			cout<<0<<endl;
		}
		else{
			cout<<ans<<endl;
		}
	}
	return 0;
}

C++: #include <iostream>
#include <vector>
#include <string>
#include <map>
#include <queue>
using namespace std;
#define rep(i,n) for (int i=0; i < (n); i++)

int dx[] = {0, 1, 0, -1};
int dy[] = {-1, 0, 1, 0};
const int MAX_W = 31;

struct Point {
  int x, y, dist;
  Point(int x, int y, int dist) : x(x), y(y), dist(dist) {}
};

int main() {

  string kabe = "";
  rep(i, 2*MAX_W+4) kabe += "1";

  int w, h;
  while(cin >> w >> h, w || h) {
    vector<string> maze;
    maze.push_back(kabe); // 利便のため、迷路の周り(ここでは上側)を壁で囲う
    string s;
    getline(cin, s);
    rep(i, 2*h - 1) {
      getline(cin, s);
      if (s.size() < 2*w - 1) s += " "; // 入力の末尾の空白を補う
      s = "1" + s + "1"; // 左右に壁
      maze.push_back(s);
    }
    maze.push_back(kabe); // 下側に壁

    queue<Point> que;
    que.push(Point(1,1, 1));
    vector<vector<bool> > visited(2*h, vector<bool>(2*w, false));
    int ans = 0;
    while (!que.empty()) {
      Point p = que.front();
      que.pop();
      if (p.x == 2*w-1 && p.y == 2*h-1) {
        ans = p.dist;
        break;
      }
      if (visited[p.y][p.x]) continue;
      visited[p.y][p.x] = true;
      rep(i, 4) {
        int nx = p.x + dx[i];
        int ny = p.y + dy[i];
        if (maze[ny][nx] == '0') {
          // 一つ飛ばしで移動する
          que.push(Point(nx + dx[i], ny + dy[i], p.dist + 1));
        }
      }
    }
    cout << ans << endl;
  }
  return 0;
}