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<iostream>
#include<queue>
#include<utility>
#include<queue>
#include<string>
#define INF 10000000
using namespace std;
typedef pair<int,int> pii;
typedef queue<pii> que;

int dx[4]={1,0,-1,0},dy[4]={0,1,0,-1};
int w,h,dist[1000][1000];
int nx,ny;
string map[1000];

int bfs(){
  que q;
  pii p;
  for(int i=0;i<h;i++)
    for(int j=0;j<w;j++)dist[i][j]=INF;
  q.push(make_pair(0,0));
  dist[0][0]=0;
  while(q.size()!=0){
    p=q.front();q.pop();
    if(p.first==w && p.second==h)break;
    for(int i=0;i<4;i++){
      nx=p.first+dx[i];ny=p.second+dy[i];
      if(0<=nx && nx<w && 0<=ny && ny<h && map[ny][nx]!='1' && dist[ny+dy[i]][nx+dx[i]]==INF){
	q.push(make_pair(nx+dx[i],ny+dy[i]));
	//cout<<"ny is "<<ny<<" nx is "<<nx<<endl;
	//cout<<"dist is "<<dist[p.second][p.first]<<endl;
	map[ny][nx]=1;
	dist[ny+dy[i]][nx+dx[i]]=dist[p.second][p.first]+1;
      }
    }
  }
  return dist[h-1][w-1];
}

int main(){
  while(cin>>w>>h,h){
    cin.ignore();
    w=2*w-1;
    h=2*h-1;
    for(int i = 0;i < h;i++) getline(cin,map[i]);   
    int ans=bfs();
    if(ans!=INF)cout<<ans+1<<endl;
    else cout<<"0"<<endl;
  }
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
 
#define REP(i, s, n) for(int i = s; i < n; ++i)
#define rep(i, n)		 REP(i, 0, n)
#define SORT(c)			 sort((c).begin(), (c).end())
#define IINF	INT_MAX
#define LLINF LLONG_MAX
#define DEBUG false
 
typedef long long				ll;
typedef pair <int, int> ii;
 
/*
struct point{
	ll x;
	ll y;
	point(){x = 0;y = 0;}
	point(ll x, ll y):x(x), y(y){}
};
*/

int dw[] = {0, 1, 0 ,-1};
int dh[] = {1, 0 ,-1, 0};
//テ、ツクツ凝・ツ渉ウテ、ツクツ甘・ツキツヲ

int main() {

	int w, h;
	while(cin >> w >> h, w, h){
		vector<vector<int>> yoko(h ,vector<int>(w+1, 1));
		vector<vector<int>> tate(h+1 ,vector<int>(w, 1));
		
		rep(i, 2*h-1){
			if(i%2==0){
				rep(j, w-1) cin >> yoko[(int)(i/2)][j+1];
			}
			else{
				rep(j, w) cin >> tate[(int)(i/2)+1][j];
			}
		}
		
		/*
		rep(i, yoko.size()){
			rep(j, yoko[i].size()) cout << yoko[i][j]<<"\t";
			cout << endl;
		}
		cout << endl;
		rep(i, tate.size()){
			rep(j, tate[i].size()) cout << tate[i][j]<<"\t";
			cout << endl;
		}
		*/
		
		queue<pair<ii, int>> qu;
		qu.push(make_pair(make_pair(0, 0), 0)); // h, w
		
		vector<vector<bool>> used(h, vector<bool>(w));
		
		int ans = 0;
		
		while(!qu.empty()){
			pair<ii, int> tmp = qu.front();
			qu.pop();
			
			int hh = tmp.first.first;
			int ww = tmp.first.second;
			
			if(used[hh][ww]) continue;
			used[hh][ww] = true;
			if(hh == h-1 && ww == w-1){
				ans = tmp.second + 1;
				break;
			}
			
			if(yoko[hh][ww] == 0) qu.push(make_pair(make_pair(hh, ww-1), tmp.second + 1));
			if(yoko[hh][ww+1] == 0) qu.push(make_pair(make_pair(hh, ww+1), tmp.second + 1));
			if(tate[hh][ww] == 0) qu.push(make_pair(make_pair(hh-1, ww), tmp.second + 1));
			if(tate[hh+1][ww] == 0) qu.push(make_pair(make_pair(hh+1, ww), tmp.second + 1));
		}
		
		cout << ans << endl;

	}

	return 0;
}