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<algorithm>
#include<utility>
#include<string>
#include<cmath>
#include<cstring>
#include<queue>
#include<map>
#include<climits>
#include<queue>

#define REP(i, n) for(int i = 0;i < n;i++)
#define REPR(i, n) for(int i = n;i >= 0;i--)
#define FOR(i, m, n) for(int i = m;i < n;i++)
#define FORR(i, m, n) for(int i = m;i >= n;i--)
#define SORT(v, n) sort(v, v+n);
#define VSORT(v) sort(v.begin(), v.end());
#define llong long long
#define pb(a) push_back(a)
using namespace std;
typedef pair<int, int> P;
typedef long long int ll;
typedef pair<ll,ll> LLP;
int dx[4] = {1,0,0,-1};
int dy[4] = {0,1,-1,0};
#define INF 1000000007
#define MOD 1000000007
#define ARRAY_MAX 70

char mp[ARRAY_MAX][ARRAY_MAX];
int sx,sy;//スタート
int gx,gy;//ゴール
int h,w;
int d[ARRAY_MAX][ARRAY_MAX];

int bfs(){

    queue<P> que;
    REP(i,ARRAY_MAX){
        REP(j,ARRAY_MAX){
            d[i][j] = INF;//最短距離の初期化
        }
    }

    que.push(P(sy,sx));//y,xの順
    d[sy][sx] = 0;

    while(que.size()){

        P p = que.front();//first:y,second:x
        que.pop();
        if(p.first == gy && p.second == gx){
            break;
        }
        for(int i = 0;i < 4;i++){
            int ny = p.first + dy[i];
            int nx = p.second + dx[i];

            if(0 <= nx && nx < 2*w-1 && 0 <= ny && ny < 2*h-1 && mp[ny][nx] != '*' && d[ny][nx] == INF){
                //移動先が配列内かつ道である場合
                que.push(P(ny,nx));

                if((i == 0 && nx % 2 == 1) || (i == 1 && ny % 2 == 1) || (i == 2 && ny % 2 == 1) || (i == 3 && nx % 2 == 1)){
                    d[ny][nx] = d[p.first][p.second];
                }else{
                    d[ny][nx] = d[p.first][p.second] + 1;
                }
            }
        }
    }
    return d[gy][gx];
}



int main(){

    while(cin >> w >> h,w){
        
        sx = sy = 0;
        gx = 2*w-2;
        gy = 2*h-2;
        REP(i,ARRAY_MAX){
            REP(j,ARRAY_MAX){
                //とりあえず全て*で埋める
                //道は後で置き換える
                mp[i][j] = '*';
            }
        }

        REP(i,2*h-1){

            if(i % 2 == 0){
                //縦棒を構築
                for(int j = 0;j < 2*w;j+=2){
                    mp[i][j] = '&';//道に直す
                }
                REP(j,w-1){
                    int a;
                    cin >> a;
                    if(!a){
                        //壁がないなら道に直す
                        mp[i][2*j+1] = '&';
                    }else{
                        mp[i][2*j+1] = '*';
                    }
                }
            }else{
                //横棒を構築
                REP(j,w){
                    int a;
                    cin >> a;
                    if(!a){
                        //壁でないなら道に直す
                        mp[i][2*j] = '&';
                    }else{
                        mp[i][2*j] = '*';
                    }
                }
            }
        }

        //迷路の構築終了
        int ans = bfs();
        if(ans == INF){
            cout << "0" << endl;
        }else{
            cout << ans+1 << endl;
        }
    }

    return 0;
}