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

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

int main(void){

	int w, h;

	while (cin >> w >> h , w, h){
		bool x_wall[40][40] = { false }, y_wall[40][40] = { false };
		bool used[40][40];
		queue<pair <int, pair<int, int> > > que;

		for (int j = 0; j < h; j++){
			for (int i = 0; i < w; i++) used[j][i] = false;
		}

		for (int i = 0; i < w; i++) y_wall[0][i] = true;
		
		for (int j = 0; j < h - 1; j++){
			int buff;
			x_wall[j][0] = true;
			for (int i = 1; i < w; i++) cin >> x_wall[j][i];
			x_wall[j][w] = true;

			for (int i = 0; i < w; i++) cin >> y_wall[j + 1][i];
			
		}

		x_wall[h-1][0] = true;
		for (int i = 1; i < w; i++) cin >> x_wall[h-1][i];
		x_wall[h-1][w] = true;

		for (int i = 0; i < w; i++) y_wall[h][i] = true;

		que.push(make_pair(1, make_pair(0, 0)));

		/*
		for (int j = 0; j < h; j++){
			for (int i = 0; i < w; i++){
				cout << x_wall[j][i] << y_wall[j][i] << "\t";
			}
			cout << endl;
		}
		*/

		bool flag = false;

		while (!que.empty()){
			pair <int, pair<int, int> > nxy = que.front();
			que.pop();

			int x = nxy.second.first;
			int y = nxy.second.second;
			if (used[y][x] || x < 0 || w < x || y < 0 || h < y)continue;

			used[y][x] = true;

			if (x == w - 1 && y == h - 1){
				cout << nxy.first << endl;
				flag = true;
				while (!que.empty()) que.pop();
				break;
			}

			//cout << nxy.first << "\t" << x << "\t" << y << endl;

			if (!x_wall[y][x] && !used[y][x - 1]) que.push(make_pair(nxy.first + 1, make_pair(x - 1, y)));
			if (!y_wall[y][x] && !used[y - 1][x]) que.push(make_pair(nxy.first + 1, make_pair(x, y - 1)));
			if (!x_wall[y][x + 1] && !used[y][x + 1]) que.push(make_pair(nxy.first + 1, make_pair(x + 1, y)));
			if (!y_wall[y + 1][x] && !used[y + 1][x]) que.push(make_pair(nxy.first + 1, make_pair(x, y + 1)));

		}

		if (!flag) cout << 0 << endl;

	}

	return 0;
}

/*
for(i=0;i<N;i++){
cin >> X[i];
}


for(i=0;i<N;i++){
for(j=0;j<N;j++){
cin >> X[i][j];
}
}
*/