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 <string>
#include <vector>
#include <queue>
using namespace std;

int map[100][100] = {};
int w, h;

void reset(){
	for(int i = 0;i<100;i++){
		for(int j = 0;j<100;j++){
			map[i][j] = 0;
		}
	}
}

int main(){
	while(cin >> w >> h){
		if (!w && !h) break;
		reset();
		for(int i = 0;i<2 * h -1;i++){
			if (i % 2 == 0) {
				for (int j = 0; j < w - 1; j++) {
					cin >> map[i][2 * j + 1];
				}
			}
			else {
				for (int j = 0; j < w; j++) {
					cin >> map[i][2 * j];
				}
			}
		}
		queue<pair<int, int>> que;
		que.push(pair<int, int>(0, 0));
		int n = 0;
		while(que.size()){
			int que_size = que.size();
			for(int x = 0;x<que_size;x++){
				pair<int, int> now = que.front();
				que.pop();
				map[now.first * 2][now.second * 2] = n;
				if( now.first < h-1 && map[now.first * 2 + 1][now.second * 2] == 0 && map[(now.first + 1) * 2][now.second * 2] == 0){
					que.push(pair<int, int>(now.first + 1, now.second));
				}
				if (now.first > 0 && map[now.first * 2 - 1][now.second * 2] == 0 && map[(now.first - 1) * 2][now.second * 2] == 0) {
					que.push(pair<int, int>(now.first - 1, now.second));
				}
				if (now.second < w-1 && map[now.first * 2][now.second * 2 + 1] == 0 && map[now.first * 2][(now.second + 1) * 2] == 0) {
					que.push(pair<int, int>(now.first, now.second + 1));
				}
				if (now.second > 0 && map[now.first * 2][now.second * 2 - 1] == 0 && map[now.first * 2][(now.second - 1) * 2] == 0) {
					que.push(pair<int, int>(now.first, now.second - 1));
				}
			}
			n++;
		}
		if(map[(h - 1) * 2][(w - 1) * 2] != 0) cout << map[(h-1) * 2][(w-1) * 2]  + 1 << endl;
		else cout << 0 << endl;
	}
	return 0;
}

C++: /*** ????????¨?????? ***/

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

int main(){
	int w, h, i, j, size, count;
	int in[1740];
	int maze[61][61];
	int hist[61][61];
	
	int dx[4]={0, 1, 0, -1}; // ????????????
	int dy[4]={-1, 0, 1, 0};
	
	cin >> w >> h;
	
	while(w||h){
		size=(w-1)*h+w*(h-1);
		for(i=0; i<size; ++i) cin >> in[i];
		for(j=0; j<2*h+1; ++j){
			for(i=0; i<2*w+1; ++i){
				hist[j][i]=-1;
			}
		}
		
		count=0;
		for(j=0; j<2*h+1; ++j){
			for(i=0; i<2*w+1; ++i){
				if(j==0 || j==2*h || i==0 || i==2*w) maze[j][i]=1;
				else if(j%2==0 && i%2==0) maze[j][i]=1;
				else if(j%2==1 && i%2==1) maze[j][i]=0;
				else{
					maze[j][i]=in[count];
					++count;
				}
			}
		}
		
		queue<pair<int, int>> qu;
		qu.push(make_pair(1, 1));
		hist[1][1]=1;
		while(!qu.empty()){
			pair<int, int> q=qu.front();
			qu.pop();
			int y=q.first, x=q.second;
			for(int k=0; k<4; ++k){
				int yy=y+dy[k], xx=x+dx[k];
				if(maze[yy][xx]==1) continue;
				yy+=dy[k];
				xx+=dx[k];
				if(hist[yy][xx]!=-1) continue;
				hist[yy][xx]=hist[y][x]+1;
				qu.push(make_pair(yy, xx));
			}
		}
		
		if(hist[2*h-1][2*w-1]==-1) cout << 0 << endl;
		else cout<< hist[2*h-1][2*w-1] << endl;
		
		cin >> w >> h;
	}
	return 0;
}