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<queue>
#include<vector>
#include<cstdio>
using namespace std;
#define max 70


class Node{
public:
	int cost;
	int x;
	int y;
	Node(int c,int _x,int _y){
		cost=c;
		x=_x;
		y=_y;
	}
};

typedef queue <Node> bq;
int map[max][max];
bool visited[max][max];
int dx[]={ 0, 1, 0,-1};
int dy[]={ 1, 0,-1, 0};
int w,h;

void init(){
	int i,j;
	for(i=0;i<max;i++){
		for(j=0;j<max;j++){
			map[i][j]=0;
			visited[i][j]=false;
		}
	}
}
void print(){
	int i,j;
	for(i=0;i<2*h-1;i++){
		if(i%2==0)cout<<"|";
		else cout<<" ";
		for(j=0;j<2*w;j++){
			if(i%2==0)printf("%s",map[i][j]?"|":" ");
			else printf("%s",map[i][j]?"_":" ");
		}
		if(i%2==0)cout<<"|";
		printf("\n");
	}
}
int bfs(){
	bq q;
	q.push(Node(1,0,0));


	while(!q.empty()){
		Node cur = q.front();q.pop();
		if(cur.x==2*(w-1) && cur.y==2*(h-1)){
			return cur.cost;
		}

		if(visited[cur.y][cur.x])continue;
		visited[cur.y][cur.x]=true;
		for(int i=0;i<4;i++){
			if(cur.y+dy[i]<0 || cur.y+dy[i]>2*(h-1) || cur.x+dx[i]<0 || cur.x+dx[i]>2*(w-1)
					|| map[cur.y+dy[i]][cur.x+dx[i]]==1)continue;
			q.push(Node(cur.cost+1, cur.x+2*dx[i], cur.y+2*dy[i]));
		}

	}
	return 0;
}
int main(){
	int i,j;
	while(cin>>w>>h&&(w||h)){
		init();
		for(i=0;i<2*h-1;i++){
			int k;
			if(i%2==0){
				for(j=0,k=1;j<w-1;j++){
					cin>>map[i][k];
					k+=2;
				}
			}
			else{
				for(j=0,k=0;j<w;j++){
					cin>>map[i][k];
					k+=2;
				}
			}
		}
		//print();
		cout<<bfs()<<endl;
	}
	return 0;
}

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

using namespace std;

typedef vector<int> VI;
typedef vector< VI > VVI;
typedef vector< VVI > VVVI;


int MAP(VVI &m, int i, int j){

	int w = m[0].size();
	int h = m.size();

	if(!( 0 <= i && i <= h && 0 <= j && j <= w)){
		return 0;
	}

	if(m[i][j] == 0){
		return 0;
	}
	else if(m[i][j] == 1){
		m[i][j] = 0;
		MAP(m, i - 1, j - 1);
		MAP(m, i, j - 1);
		MAP(m, i + 1, j - 1);
		MAP(m, i - 1, j);
		MAP(m, i + 1, j);
		MAP(m, i - 1, j + 1);
		MAP(m, i, j + 1);
		MAP(m, i + 1, j + 1);
	}

	return 1;
}

int main(){
	int w, h;

	while(true){
		cin >> w >> h;

		if(w == 0 && h == 0){
			break;
		}

		VVI map(h + 1, VI(w + 1, 0));

		for(int i = 0; i < h; i++){
			for(int j = 0; j < w; j++){
				cin >> map[i][j];
			}
		}

		int count = 0;

		for(int i = 0; i < h; i++){
			for(int j = 0; j < w; j++){
				count += MAP(map, i, j);
			}
		}

		cout << count << endl;
	}
}

C++: #include<map>
#include<set>
#include<list>
#include<cmath>
#include<queue>
#include<stack>
#include<cstdio>
#include<string>
#include<vector>
#include<complex>
#include<cstdlib>
#include<cstring>
#include<climits>
#include<numeric>
#include<sstream>
#include<iostream>
#include<algorithm>
#include<functional>
#include<cctype>

#define mp make_pair
#define pb push_back
#define REP(i,a,n) for(int i = a;i < (n);i++)
#define rep(i,n) for(int i = 0;i < (n);i++)
#define all(s) s.begin(), s.end()
#define rall(s) s.rbegin(), s.rend()
#define range(x,min,max) ((min) <= (x) && (x) <= (max))

using namespace std;

typedef long long LL;
typedef vector<int> VI;
typedef vector<vector<int> > VII;
typedef vector<string> VS;
typedef vector<bool> VB;
typedef pair<int,int> PII;

const int DX[]={1,0,-1,0},DY[]={0,-1,0,1};

int w, h;
int MAP[60][60];

#define x first
#define y second

int bfs() {
	VII dist(2 * h - 1, VI (2 * w - 1,INT_MAX));
	queue<PII> que;
	que.push(mp(0, 0));
	dist[0][0] = 0;
	while(!que.empty()){
		PII now = que.front();
		MAP[now.y][now.x] = 0;
		que.pop();
		rep(i, 4){
			int nx = now.x + DX[i];
			int ny = now.y + DY[i];
			if(range(nx, 0, 2 * w - 2) && range(ny, 0, 2 * h - 2) && !MAP[ny][nx]){
				if(dist[now.y][now.x] + 1 >= dist[ny + DY[i]][nx + DX[i]]) continue;
				dist[ny + DY[i]][nx + DX[i]] = dist[now.y][now.x] + 1;
				que.push(mp(nx + DX[i], ny + DY[i]));
			}
		}
	}
	return dist[2 * h - 2][2 * w - 2] != INT_MAX? dist[2 * h - 2][2 * w - 2] : -1;
}

int main(){
	cin.tie(0);
   	ios::sync_with_stdio(false);
	
	while(1){
		rep(i, 60){
			rep(j, 60){
				MAP[i][j] = 0;
			}
		}
		cin >> w >> h;
		if(w == 0 && h == 0) break;
		for(int i = 0;i < 2 * h - 1;i++){
			int size = i % 2? w : w - 1;
			for(int j = 0;j < size;j++){
				int a;
				cin >> a;
				MAP[i][2 * j + !(i % 2)] = a;
			}
		}
		cout << bfs() + 1 << endl;
	}
	return 0;
}