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++: //queue ???????????????

#include <iostream>
#include <queue>
#define inf 1e9
#define mp make_pair
#define f first
#define s second 
using namespace std;
int h1[4] = {0,1,0,-1},w1[4] = {1,0,-1,0};
int h2[4] = {0,2,0,-2},w2[4] = {2,0,-2,0};
int res,H,W;
int grid[103][103];
int ans[103][103];
bool check1(int y, int x){
	if(grid[y][x] == 1)return false;
	return true;
}

bool check2(int y, int x){
	if(y <= 0 || x <= 0 || y > H*2 || x > W*2)return false;
	return true;
}

void solve(){
	queue<pair<int,int> > q;
	int x,y;
	x = y = 1;
	pair<int,int> p;
	q.push(mp(y,x));
	ans[y][x] = 1;
	while(q.size()){
		p = q.front();
		x = p.s;
		y = p.f;
		q.pop();
		if(p == mp((H*2)-1,(W*2)-1))break;
		for(int i = 0;i < 4;i++){
			if(check1(y+h1[i],x+w1[i])){
				if(check2(y+h2[i],x+w2[i])){
					if(ans[y+h2[i]][x+w2[i]] == inf){
						q.push(mp(y+h2[i],x+w2[i]));
						ans[y+h2[i]][x+w2[i]] = ans[y][x] + 1;

					}
				}
			}
		}
	}
}


int main(){
	int n;
	while(1){
		cin >> W >> H;
		if(W == 0)break;
		for(int i = 0;i < 103;i++){
			for(int j = 0;j < 103;j++){
				ans[i][j] = inf;
			}
		}
		for(int i = 0;i < H*2 + 1;i++){
			for(int j = 0;j < W*2 + 1;j++){
				if(j == 0 || i == 0 || j == W*2 || i == H*2)grid[i][j] = 1;
				else if(i%2 == 1 && j%2 == 0){
					cin >> n;
					grid[i][j] = n;
				}
				else if(i%2 == 1 && j%2 == 1){
					grid[i][j] = 0;
				}
				else if(i%2 == 0 && j%2 == 0){
					grid[i][j] = 1;
				}
				else if(i%2 == 0 && j%2 == 1){
					cin >> n;
					grid[i][j] = n;
				}
			}
		}
		solve();
		res = ans[(H*2)-1][(W*2)-1];
		if(res == inf)cout << 0 << endl;
		else cout << res <<endl;
		
		
	}
	return 0;
}