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 <cstring>
#include <iostream>
#include <queue>
using namespace std;
const int WH_MAX = 30;
int field[2 * WH_MAX - 1][WH_MAX * 2 - 1];
int w, h;
int visited[2 * WH_MAX - 1][WH_MAX * 2 - 1];
const int dx[] = {1, 0, -1, 0};
const int dy[] = {0, 1, 0, -1};

int solve() {
	queue<pair<int, int> > que;
	memset(visited, 0, sizeof(visited));
	que.push(make_pair(0, 0));
	visited[0][0] = 1;
	while (!que.empty()) {
		pair<int, int> current = que.front();
		que.pop();
		const int x = current.first;
		const int y = current.second;
		for (int i = 0; i < 4; i++) {
			const int nextX = x + dx[i] * 2;
			const int nextY = y + dy[i] * 2;
			if (0 <= nextX && nextX < w * 2 - 1 && 0 <= nextY && nextY < h * 2 - 1
					&& !field[y + dy[i]][x + dx[i]] && !visited[nextY][nextX]) {
				que.push(make_pair(nextX, nextY));
				visited[nextY][nextX] = visited[y][x] + 1;
			}
		}
	}
	return visited[h * 2 - 2][w * 2 - 2];
}

int main () {
	while (cin >> w >> h, w || h) {
		memset(field, 0, sizeof(field));
		for (int i = 0; i < h * 2 - 1; i++) {
			for (int j = 0; j < w - (i + 1) % 2; j++) {
				cin >> field[i][j * 2 + (i + 1) % 2];
			}
		}
		cout << solve() << endl;
	}
	return 0;
}

C++: #include <iostream>
#include <vector>
#include <string>
#include <cmath>
#include <algorithm>
#include <queue>

using namespace std;

int dx[] = {0,0,-1,1};
int dy[] = {1,-1,0,0};
int w,h;

void solve(int w,int h){
	int ng[32][32][4]={};
	int flag[32][32]={};
	int tmp;
	bool breakflag=0;
	for(int i=0;i<2*h-1;i++){
		if(i%2==0){
			for(int j=0;j<w-1;j++){
				cin >> tmp;
				ng[j][i/2][3]=tmp;
				ng[j+1][i/2][2]=tmp;
			}
		}
		if(i%2==1){
			for(int j=0;j<w;j++){
				cin >> tmp;
				ng[j][i/2][0]=tmp;
				ng[j][i/2+1][1]=tmp;
			}
		}
	}
	queue<pair<int,pair<int,int> > > q;
	q.push(make_pair(1,make_pair(0,0)));
	flag[0][0]=1;
	while(!q.empty()){
		pair<int,pair<int,int> >p;
		p = q.front();
		q.pop();
		int a,b;
		a = p.second.first;
		b = p.second.second;
		if(a==w-1&&b==h-1){
			cout << p.first <<endl;
			breakflag=1;
			break;
		}
		for(int i=0;i<4;i++){
			if(a+dx[i]>=0&&a+dx[i]<w&&b+dy[i]>=0&&b+dy[i]<h){
				if(ng[a][b][i]==0&&flag[a+dx[i]][b+dy[i]]==0){
					q.push(make_pair(p.first+1,make_pair(a+dx[i],b+dy[i])));
					flag[a+dx[i]][b+dy[i]]=1;
				}				
			}
		}
	}
	if(breakflag==0){
		cout << 0 <<endl;
	}
}


int main(){
	while(1){
		cin >> w >> h;
		if(w==0&&h==0)break;
		solve(w,h);
	}
	return 0;
}