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 <queue>
#include <vector>
#include <iostream>

#define INF (1 << 29)

using namespace std;

const int dx[4] = { 0, 1, 0, -1 };
const int dy[4] = { -1, 0, 1, 0 };

int main()
{
	int H, W, T; vector<vector<vector<bool> > > M;

	while (true)
	{
		scanf("%d", &W);
		scanf("%d", &H);

		if (W == 0 && H == 0) { break; }

		M = vector<vector<vector<bool> > >(H, vector<vector<bool> >(W, vector<bool>(4, false)));

		for (int i = 0; i < W; i++)
		{
			M[0][i][0] = true;
		}

		for (int i = 0; i < H; i++)
		{
			M[i][W - 1][1] = true;
		}

		for (int i = 0; i < W; i++)
		{
			M[H - 1][i][2] = true;
		}
		
		for (int i = 0; i < H; i++)
		{
			M[i][0][3] = true;
		}

		for (int i = 0; i < 2 * H - 1; i++)
		{
			for (int j = 0; j < (i % 2 == 0 ? W - 1 : W); j++)
			{
				scanf("%d", &T);

				if (T == 1)
				{
					if (i % 2 == 0)
					{
						M[i / 2][j][1] = true;
						M[i / 2][j + 1][3] = true;
					}
					else
					{
						M[i / 2][j][2] = true;
						M[i / 2 + 1][j][0] = true;
					}
				}
			}
		}

		vector<vector<int> > dp(H, vector<int>(W, INF)); dp[0][0] = 1;

		queue<pair<int, int> > que; que.push(make_pair(0, 0));

		while (!que.empty())
		{
			pair<int, int> p1 = que.front(); que.pop();

			int x = p1.first;
			int y = p1.second;

			for (int dir = 0; dir < 4; dir++)
			{
				if (M[y][x][dir] == false)
				{
					if (dp[y + dy[dir]][x + dx[dir]] == INF)
					{
						dp[y + dy[dir]][x + dx[dir]] = dp[y][x] + 1;

						que.push(make_pair(x + dx[dir], y + dy[dir]));
					}
				}
			}
		}

		if (dp[H - 1][W - 1] == INF)
		{
			printf("0\n");
		}
		else
		{
			printf("%d\n", dp[H - 1][W - 1]);
		}
	}

	return 0;
}

C++: #include <stdio.h>
#include <iostream>
#include <vector>
#include <list>
#include <cmath>
#include <fstream>
#include <algorithm>
#include <string>
#include <queue>
#include <set>
#include <map>
#include <complex>
#include <iterator>
#include <cstdlib>
#include <sstream>

using namespace std;

#define EPS (1e-10)
#define EQ(a,b) (abs((a) - (b)) < EPS)
#define EQV(a,b) (EQ((a).real(),(b).real()) && EQ((a).imag(),(b).imag()))

typedef complex<double> P;
typedef long long ll;

const int MAX_SIZE = 10000;

int w,h;


int yoko[31][31];
int tate[31][31];

void bfs(){
	queue<pair<int,int> > *prv = new queue<pair<int,int> >();
	queue<pair<int,int> > *nxt = new queue<pair<int,int> >();
	
	int dy[] = {-1,0,0,1};
	int dx[] = {0,-1,1,0};

	bool passed[31][31];
	for(int i = 0; i < 31; i++)
		fill(passed[i],passed[i]+31,false);

	prv->push(make_pair(0,0));
	int cnt = 0;
	while(prv->size()){
		cnt++;
		while(prv->size()){
			pair<int,int> place = prv->front();
			prv->pop();
			if(passed[place.first][place.second])
				continue;

			passed[place.first][place.second] = true;
			if(place.second == w-1 && place.first == h-1){
				delete prv,nxt;
				cout << cnt << endl;
				return;
			}
			for(int i = 0; i < 4; i++){
				int xx = place.second + dx[i];
				int yy = place.first + dy[i];
				if(xx >= 0 && xx < w && yy >= 0 && yy < h){
					if(!passed[yy][xx]){
						if((dx[i] == -1 && !yoko[yy][xx]) || (dx[i] == 1 && !yoko[yy][xx-1]) 
							|| (dy[i] == -1 && !tate[yy][xx]) || (dy[i] == 1 && !tate[yy-1][xx])){
							nxt->push(make_pair(yy,xx));
						}
					}
				}
			}
		}
		swap(prv,nxt);
	}
	delete prv,nxt;
	cout << 0 << endl;
}

int main(){

	while(cin >> w >> h && !(w == 0 && h == 0)){
		for(int i = 0; i < 31; i++){
			fill(yoko[i],yoko[i]+31,0);
			fill(tate[i],tate[i]+31,0);
		}

		for(int i = 0; i < h; i++){
			for(int j = 0; j < w-1; j++){
				cin >> yoko[i][j];
			}
			if(i != h - 1){
				for(int j = 0; j < w; j++){
					cin >> tate[i][j];
				}
			}
		}
		bfs();
	}

	return 0;
}