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 <algorithm>
#include <vector>
using namespace std;

const int INF = 9999999;

vector<vector<int>> cost;
int d[1000];
bool used[1000];
int V;

void calc() {
	fill(d, d + V, INF);
	fill(used, used + V, false);
	d[0] = 0;

	while (true) {
		int v = -1;
		for (int u = 0; u < V; u++) {
			if (!used[u] && (v == -1 || d[u] < d[v])) v = u;
		}

		if (v == -1)break;
		used[v] = true;
		for (int u = 0; u < V; u++) {
			d[u] = min(d[u], d[v] + cost[v][u]);
		}
	}
}

int main() {
	int w, h;
	while (cin >> w >> h , w != 0 || h != 0) {
		V = w * h;
		cost = vector<vector<int>>(h * w, vector<int>(h * w, INF));
		for (int i = 0; i < 2 * h - 1; i++) {
			int wall;
			if (i % 2 == 0) {
				for (int j = 0; j < w - 1; j++) {
					cin >> wall;
					if (wall == 0) {
						cost[(i / 2) * w + j][(i / 2) * w + j + 1] = cost[(i / 2) * w + j + 1][(i / 2) * w + j] = 1;
					}
				}
			}
			else {
				for (int j = 0; j < w; j++) {
					cin >> wall;
					if (wall == 0) {
						cost[(i / 2) * w + j][(i / 2 + 1) * w + j] = cost[(i / 2 + 1) * w + j][(i / 2) * w + j] = 1;
					}
				}
			}
		}
		calc();
		int dist = d[h * w - 1];
		if (dist == INF)
			cout << 0 << endl;
		else
			cout << dist + 1 << endl;
	}
}

C++: #include <iostream>
#include <queue>
#include <vector>
using namespace std;
int w,h;
char map[200][200];
class Node{
public:
	int x,y;
	int c;
	Node(int _x,int _y,int _c):x(_x),y(_y),c(_c){

	}
};
void show(){
	for(int i=0;i<h*2-1;i++){
		for(int j=0;j<w*2-1;j++)cout<<map[i][j];
		cout<<endl;
	}
	cout<<endl;
}
bool visited[200][200];
int dx[]={1,0,-1,0};
int dy[]={0,-1,0,1};
int bfs(){
	for(int i=0;i<100;i++)fill(visited[i],visited[i]+100,false);
	queue<Node> q;
	q.push(Node(0,0,1));
	visited[0][0]=true;
	int gw=2*w-2;
	int gh=2*h-2;
	while(!q.empty()){
		Node cur=q.front();q.pop();
//		map[cur.y][cur.x]='1';
		show();
		if(cur.x==gw&&cur.y==gh)return cur.c;
		for(int i=0;i<4;i++){
			int nx=cur.x+dx[i];
			int ny=cur.y+dy[i];
			if(nx<0||ny<0||nx>gw||ny>gh||map[ny][nx]=='1')continue;
			nx=nx+dx[i];
			ny=ny+dy[i];
			if(nx<0||ny<0||nx>gw||ny>gh||map[ny][nx]=='1')continue;
			map[cur.y][cur.x]='1';
			if(visited[ny][nx])continue;
			visited[ny][nx]=true;
			q.push(Node(nx,ny,cur.c+1));
		}
	}
	return 0;
}
void solve(){
	cout<<bfs()<<endl;
}
int main(){
	while(cin>>w>>h&&(w||h)){
		for(int i=0;i<100;i++)for(int j=0;j<100;j++)map[i][j]='0';
		int hline=h*2-1;
		for(int i=0;i<hline;i++){
			if(i%2){
				for(int j=0;j<w;j++)cin>>map[i][2*j];
			}
			else {
				for(int j=0;j<w-1;j++)cin>>map[i][1+2*j];

			}
		}
//		show();
		solve();
	}
	return 0;
}

C++: #include <iostream>
#include <queue>

using namespace std;

int h, w;
// maze[y][x][i] = 1 -> (x, y) は (dx[i], dy[i]) 方向に移動可能
int maze[100][100][4];
int dist[100][100];
int dx[4] = {-1, 0, 0, 1};
int dy[4] = {0, 1, -1, 0};

struct sets { int x, y, d; };

void init() {
  for (int i = 0; i < 100; i++) {
    for(int j = 0; j < 100; j++) {
      for (int k = 0; k < 4; k++) {
        maze[i][j][k] = 0;
      }
    }
  }
  for (int i = 0; i < 100; i++) {
    for (int j = 0; j < 100; j++) {
      dist[i][j] = -1; 
    }
  }
}

int bfs() {
  queue<sets> q;
  q.push( sets{0, 0, 0} );
  dist[0][0] = 0;

  while (!q.empty()) {
    sets cur = q.front(); q.pop();
    int x = cur.x;
    int y = cur.y;
    int d = cur.d;
    for (int i = 0; i < 4; i++) {
      int nx = x + dx[i];
      int ny = y + dy[i];

      if ( maze[y][x][i] == 0 ) { continue; }
      if ( dist[ny][nx] != -1 ) { continue; }

      q.push( sets{nx, ny, d+1} );
      dist[ny][nx] = d+1;
    }
  }
  return dist[h-1][w-1] + 1;
}

int main() {
  while (cin >> w >> h) {
    if (h == 0 && w == 0) { break; }
    init();
    for (int i = 0; i < 2*h-1; i++) {
      if (i & 1) {
        for (int j = 0; j < w; j++) {
          int t; cin >> t;
          if (t == 0) {
            maze[i/2][j][1] = 1;
            maze[i/2+1][j][2] = 1;
          }
        }
      } else {
        for (int j = 0; j < w-1; j++) {
          int t; cin >> t;
          if (t == 0) {
            maze[i/2][j][3] = 1;
            maze[i/2][j+1][0] = 1;
          }
        }
      }
    }
    cout << bfs() << endl;
  }
  return 0;
}