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<algorithm>
#include<iostream>
#include<vector>
#include<string>
#include<queue>
#include<map>

using namespace std;

#define reps(i,f,n) for(int i=f;i<int(n);i++)
#define rep(i,n) reps(i,0,n)

typedef vector<int> vi;
typedef vector<vi> vii;
typedef pair<int,int> pii;

class T{
	public:
	int x,y,ans;
	T(int x,int y,int ans):x(x),y(y),ans(ans){}
};

int main(){
	int w,h;
	A:cin>>w>>h;
	if(w==0)return 0;
	
	int t[31][31]={0};
	int z[31][31]={0};
	rep(i,h){
		rep(j,w-1){
			cin>>t[j][i];
		}
		if(i!=h-1)rep(j,w){
			cin>>z[j][i];
		}
	}
	
	/*
	rep(i,h){
		rep(j,w)printf("%d ",t[i][j]);puts("");
		rep(j,w)printf("%d ",y[i][j]);puts("");
		puts("");
	}*/
	
	queue<T> que;
	que.push(T(0,0,0));
	
	int visit[31][31]={0};
	int ans = -2;
	
	while(1){
		if(que.empty())break;
		
		T u = que.front();
		que.pop();
		
		if(visit[u.x][u.y]==1)continue;
		visit[u.x][u.y]=1;
		
		if(u.x==w-1 && u.y==h-1){
			ans = u.ans;
			break;
		}
		
		int x = u.x;
		int y = u.y;
		if(x<w-1 && t[x][y]!=1)que.push(T(x+1,y,u.ans+1));
		if(y<h-1 && z[x][y]!=1)que.push(T(x,y+1,u.ans+1));
		if(x>0 && t[x-1][y]!=1)que.push(T(x-1,y,u.ans+1));
		if(y>0 && z[x][y-1]!=1)que.push(T(x,y-1,u.ans+1));
	}
	
	printf("%d\n",ans+1);
	
	goto A;
}

C++: 
#include<iostream>
#include<queue>
using namespace std;

int main(){
  int w,h;
  int map[30][30];		//?£???????,???,???,??????????????????????????????1,2,4,8????????????
  while(cin >> w >> h && w>0 && h>0){
    for(int i=0;i<h;i++)
      for(int j=0;j<w;j++)
        map[i][j]=0;

    for(int i=0;i<h;i++){
      for(int j=0;j<w;j++){
        if(i==0) map[i][j]|=1;
        else{
          int wall;
          cin >> wall;
          if(wall==1){
            map[i-1][j]|=8;
            map[i][j]|=1;
          }
        }
        if(i==h-1) map[i][j]|=8;
      }

      map[i][0]|=2;
      for(int j=1;j<w;j++){
        int wall;
        cin >> wall;
        if(wall==1){
          map[i][j-1]|=4;
          map[i][j]|=2;
        }
      }
      map[i][w-1]|=4;
    }

    int d[30][30];
    for(int i=0;i<h;i++)
      for(int j=0;j<w;j++)
        d[i][j]=0;

    d[0][0]=1;
    queue<int> cur;
    cur.push(0*w+0);
    int sh[4]={-w,-1,1,w};

    while(!cur.empty()){
      for(int i=0;i<4;i++){
        if((map[cur.front()/w][cur.front()%w] & (1<<i))==0 && d[(cur.front()+sh[i])/w][(cur.front()+sh[i])%w]==0){
          d[(cur.front()+sh[i])/w][(cur.front()+sh[i])%w]=d[cur.front()/w][cur.front()%w]+1;
          cur.push(cur.front()+sh[i]);
        }
      }
      cur.pop();
    }

    cout << d[h-1][w-1] << endl;

    return 0;
  }
}

C++: #include<bits/stdc++.h>
typedef long long ll;
typedef unsigned long long ull;
using namespace std;
#define pb push_back
int dy[]={0, 0, 1, -1, 1, 1, -1, -1};
int dx[]={1, -1, 0, 0, 1, -1, -1, 1};

#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n) for (int i=0;i<(n);i++)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
#define mp make_pair
#define fi first
#define sc second
typedef pair<int ,int>P;
int h,w;
vector<int>m[100] ;
int d[100][100];
int main(){
	while(1) {
		cin >> w >> h;

		if(w == 0)
			break;

		REP(i,100) {
			m[i].clear();
		}


		REP(i,2 * h - 1) {
			if(i % 2 == 0) {
				REP(j,w - 1) {
					m[i].pb(-1);
					m[i].pb(-1);
					cin >> *(m[i].end() - 1);
				}
				m[i].pb(-1);
			}else {
				REP(j,w) {
					m[i].pb(-1);
					cin >> *(m[i].end() - 1);
					m[i].pb(-1);
				}
			}
		}
		REP(i,h){
			REP(j,w){
				d[i][j] = -1;
			}
		}

		queue<P> que;

		que.push(P(0,0));
		d[0][0] = 1;
		while(d[h-1][w-1] == -1 && !que.empty()){
			P masu = que.front();
			que.pop();

			REP(i,4){
				int x = masu.fi * 2 +dx[i];
				int y = masu.sc * 2 +dy[i];
				if (0 <=  x && x <2 * h -1 && 0 <= y && y <=2 * w - 1 && m[x][y]== 0){
					//すすめる
					x += dx[i];
					y += dy[i];

					if(d[x/2][y/2] > -1)continue;

					d[x/2][y/2] = d[masu.fi][masu.sc]+1;

					que.push(P(x / 2,y / 2));

				}

			}

		}
		if(d[h-1][w-1] == -1) cout << 0 << endl;
		else cout <<d[h-1][w-1] <<endl; 
	}

	return 0;
}