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 <vector>
#include <queue>

using namespace std;

typedef pair<int, int> P;
typedef pair<int, P> Q;

int mp[35][35][35][35] = { 0 };

int main() {
	int w, h;
	while (cin >> w >> h) {
		if (w == 0 && h == 0) {
			break;
		}
	
		for (int i = 0; i < 35; i++) {
			for (int j = 0; j < 35; j++) {
				for (int k = 0; k < 35; k++) {
					for (int l = 0; l < 35; l++) {
						mp[i][j][k][l] = 0;
					}
				}
			}
		}

		int wall;

		for (int i = 0; i < 2 * h - 1; i++) {
			if (i % 2 == 0) {
				for (int j = 0; j < w - 1; j++) {
					cin >> wall;
					mp[j][i / 2][j + 1][i / 2] = wall;
					//cout << i << 'a' << j << endl;
				}
			}
			else {
				for (int j = 0; j < w; j++) {
					cin >> wall;
					mp[j][i / 2][j][(i / 2) + 1] = wall;
					//cout << i << 'a' << j << endl;
				}
			}
		}
		//cout << 'a' << endl;
		int mpp[35][35] = { 0 };
		queue<Q> q;
		q.push(Q(1, P(0, 0)));
		mpp[0][0] = 1;

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

		int ans = 0;

		while (!q.empty()) {
			bool hh = false;
			Q qq = q.front();
			q.pop();
			P p = qq.second;
			//cout << qq.first << ' '<< p.first << ' ' << p.second << endl;
			for (int i = 0; i < 4; i++) {
				if (0 <= p.first + dx[i] && p.first + dx[i] < w && 0 <= p.second + dy[i] && p.second + dy[i] < h) {
					if (mpp[p.first + dx[i]][p.second + dy[i]] == 0 && mp[p.first][p.second][p.first + dx[i]][p.second + dy[i]] == 0) {
						if (p.first + dx[i] == w - 1 && p.second + dy[i] == h - 1) {
							hh = true;
							ans = qq.first + 1;
							break;
						}
						else {
							q.push(Q(qq.first + 1, P(p.first + dx[i], p.second + dy[i])));
							mpp[p.first + dx[i]][p.second + dy[i]] = 1;
						}
					}
				}
			}
			if (hh) {
				break;
			}
		}
		cout << ans << endl;
	}
	return 0;
}

C++: #include<iostream>
#include<queue>
#include<cstring>
using namespace std;

#define rep(i,n) for(int i=0;i<n;i++)
#define REP(n) rep(i,n)

struct tile
{
    int x,y,t;
    tile(int x,int y,int t):x(x),y(y),t(t){};
};

const int MAX = 32;
int dx[] = {-1,1,0,0};
int dy[] = {0,0,-1,1};
int T=3,B=2,R=0,L=1;


int checkable[MAX][MAX];
int wall[MAX][MAX][4];
int w,h,temp;

int main()
{
    while(cin >> w >> h &&(w || h))    {
        memset(checkable,1,sizeof(checkable));
        memset(wall,1,sizeof(wall));
        rep(j,h)
        {
            rep(i,w-1)
            {
                cin >> temp;
                if(!temp){wall[i][j][R] = 0;wall[i+1][j][L] = 0;}
            }
            if(j==h-1) break;
            rep(i,w)
            {
                cin >> temp;
                if(!temp){wall[i][j][B] = 0;wall[i][j+1][T] = 0;}
            }
        }
        //cout << "input fin" << w << h << endl;
        queue<tile> q;
        q.push(tile(0,0,1));
        int ans = 0;

        while(!(q.empty()))
        {
            tile t = q.front();q.pop();
            //cout << t.x << " " << t.y << endl;

            if(t.x == (w-1) && t.y ==( h-1)){ans = t.t; break;}

            REP(4)if(!(wall[t.x+dx[i]][t.y+dy[i]][i]) &&checkable[t.x+dx[i]][t.y+dy[i]])
            {
                checkable[t.x+dx[i]][t.y+dy[i]] = 0;
                q.push(tile(t.x+dx[i],t.y+dy[i],t.t + 1));
            }
        }
        cout << ans << endl;
    }

    return 0;
}

C++: #include<iostream>
#include<queue>
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;
		}
	}
}

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;
				}
			}
		}
		cout<<bfs()<<endl;
	}
	return 0;
}