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>
using namespace std;

vector<int> ans;

int sarch_way(int w[32][32],int h[32][32],int location_status,int y,int x,int turn,int height){
	if(y==height){
/*-------------------------------------------------*/
		for(int i=0;i<height;i++){
			for(int j=0;j<12;j++){
				if(w[i][j]==1)      cout<<"|■";
				else if(w[i][j]==2) cout<<"|□";
				else 			cout<<"|  ";
			}
			cout<<"|"<<endl;
			for(int j=0;j<13;j++){
				if(h[i][j]==1) 	cout<<"|  ";
				else if(h[i][j]==2) cout<<"o  ";
				else           	cout<<"   ";
			}
			cout<<endl;
		}
		for(int j=0;j<12;j++){
			if(w[height][j]==1) 	cout<<"|■";
			else if(w[height][j]==2) cout<<"|□";
			else                	cout<<"|  ";
		}
		cout<<"|"<<endl<<endl;
/*------------------------------------------------------*/
		return turn;
	}
	int temp=0;
	turn++;

		/*----迷路を図示するためのテスト----
		for(int i=0;i<height;i++){
			for(int j=0;j<12;j++){
				if(w[i][j]==1) cout<<"|■";
				else cout<<"|  ";
			}
			cout<<"|"<<endl;
			for(int j=0;j<13;j++){
				if(h[i][j]==1) cout<<"|  ";
				else cout<<"   ";
			}
			cout<<endl;
		}
		for(int j=0;j<12;j++){
			if(w[height][j]==1) cout<<"|■";
			else cout<<"|  ";
		}
		cout<<"|"<<endl<<endl;
		/*-------------------------------*/

	
	if(location_status==1){ //マップ上から来て横線を踏んでいるとき
		w[y][x]=2;
		if(h[y][x]==0){
			location_status=4;
			temp=sarch_way(w,h,location_status,y,x,turn,height);
			if(temp) ans.push_back(temp);
		}
		if(w[y+1][x]==0){
			location_status=1;
			temp=sarch_way(w,h,location_status,y+1,x,turn,height);
			if(temp) ans.push_back(temp);
		}
		if(h[y][x+1]==0){
			location_status=3;
			temp=sarch_way(w,h,location_status,y,x+1,turn,height);
			if(temp) ans.push_back(temp);
		}
		return 0;
	}
	if(location_status==2){ //マップ下から来て横線を踏んでいるとき
		w[y][x]=2;
		if(h[y-1][x]==0){
			location_status=4;
			temp=sarch_way(w,h,location_status,y-1,x,turn,height);
			if(temp) ans.push_back(temp);
		}
		if(w[y-1][x]==0){
			location_status=2;
			temp=sarch_way(w,h,location_status,y-1,x,turn,height);
			if(temp) ans.push_back(temp);
		}
		if(h[y-1][x+1]==0){
			location_status=3;
			temp=sarch_way(w,h,location_status,y-1,x+1,turn,height);
			if(temp) ans.push_back(temp);
		}
		return 0;
	}
	if(location_status==3){ //マップ左から来て縦線を踏んでいるとき
		h[y][x]=2;
		if(h[y][x+1]==0){
			location_status=3;
			temp=sarch_way(w,h,location_status,y,x+1,turn,height);
			if(temp) ans.push_back(temp);
		}
		if(w[y][x]==0){
			location_status=2;
			temp=sarch_way(w,h,location_status,y,x,turn,height);
			if(temp) ans.push_back(temp);
		}
		if(w[y+1][x]==0){
			location_status=1;
			temp=sarch_way(w,h,location_status,y+1,x,turn,height);
			if(temp) ans.push_back(temp);
		}
		return 0;
	}
	if(location_status==4){ //マップ右から来て縦線を踏んでいるとき
		h[y][x]=2;
		if(h[y][x-1]==0){
			location_status=4;
			temp=sarch_way(w,h,location_status,y,x-1,turn,height);
			if(temp) ans.push_back(temp);
		}
		if(w[y][x-1]==0){
			location_status=2;
			temp=sarch_way(w,h,location_status,y,x-1,turn,height);
			if(temp) ans.push_back(temp);
		}
		if(w[y+1][x-1]==0){
			location_status=1;
			temp=sarch_way(w,h,location_status,y+1,x-1,turn,height);
			if(temp) ans.push_back(temp);
		}
		return 0;
	}
	return 0;
}


int main()
{
	int height,width;

	cin>>width>>height;
	while(height != 0 || width != 0){
		int h_bar[32][32],w_bar[32][32];
		ans.clear();
		//h_bar[縦][横]縦の壁 w_bar[縦][横]横の壁（外枠含む）

		for(int j=0;j<width;j++) w_bar[0][j]=1;
		for(int i=0;i<height-1;i++){
			h_bar[i][0]=1;
			for(int j=1;j<width;j++) cin>>h_bar[i][j];
			h_bar[i][width]=1;

			for(int j=0;j<width;j++) cin>>w_bar[i+1][j];
		}
		h_bar[height-1][0]=1;
		for(int j=1;j<width;j++) cin>>h_bar[height-1][j];
		h_bar[height-1][width]=1;
		for(int j=0;j<width;j++) w_bar[height][j]=1;
		w_bar[0][0]=0;
		w_bar[height][width-1]=0;
		
		/*----迷路を図示するためのテスト----
		for(int i=0;i<height;i++){
			for(int j=0;j<width;j++){
				if(w_bar[i][j]==1) cout<<"|■";
				else cout<<"|  ";
			}
			cout<<"|"<<endl;
			for(int j=0;j<width+1;j++){
				if(h_bar[i][j]==1) cout<<"|  ";
				else cout<<"   ";
			}
			cout<<endl;
		}
		for(int j=0;j<width;j++){
			if(w_bar[height][j]==1) cout<<"|■";
			else cout<<"|  ";
		}
		cout<<"|"<<endl;
		/*-------------------------------*/

		sarch_way(w_bar,h_bar,1,0,0,0,height);

		if(ans.size()==0) cout<<"0"<<endl;
		else{
			sort(ans.begin(),ans.end());
		 	cout<<ans[0]<<endl;
		}
		cin>>width>>height;
	}
}