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<string>
#include<cmath>
#include<algorithm>
#include<cctype>
#include<queue>
#include<deque>
#include<regex>
#include<stack>
#include<stdio.h>
#include<vector>
#include<set>
#include<map>
#include<iomanip>

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

typedef int long long ll;
using namespace std;
typedef pair<int, int> P;
int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};
const ll MOD = 1e9 + 7;
static const int MAX = 100;
static const int INF = (1 << 23);

int masu[31][31];
bool al[31][31];
int y[32][31];
int t[31][32];

int main() {
    int w,h;
    int masu[31][31];
    int y[32][31];
    int t[31][32];
    bool al[31][31];


    while(true){

        cin>>w>>h;
        if(w==0&&h==0)break;


        rep(i,h){rep(j,w){
                masu[i][j]=INF;
                al[i][j]=false;
            }
        }

        rep(i,h+1)rep(j,w){y[i][j]=0;}
        rep(i,h)rep(j,w+1){t[i][j]=0;}

        rep(i,w){
            y[0][i]=1;
            y[h][i]=1;
        }
        rep(i,h){
            t[i][0]=1;
            t[i][w]=1;
        }
        int yy=1;

        for(int i=0;i<2*h-1;i++){
            if(i%2==0){
                for(int j=0;j<w-1;j++){
                    cin>>t[i/2][j+1];
                }
            }else{
                for(int j=0;j<w;j++){
                    cin>>y[yy][j];
                }
                yy++;
            }
        }
        // cout<<y[1][1]<<endl;



        queue<pair<int,int>>q;
        q.push({0,0});
        masu[0][0]=1;
        while(!q.empty()){
            int mx=q.front().first;
            int my=q.front().second;
            q.pop();
            al[mx][my]=true;
            if(t[mx][my]==0){//左
                if(al[mx][my-1]==false){
                    q.push({mx,my-1});
                    al[mx][my-1]=true;
                    masu[mx][my-1]=min(masu[mx][my-1],masu[mx][my]+1);
                }
            }
            if(t[mx][my+1]==0){//右
                if(al[mx][my+1]==false){
                    al[mx][my+1]=true;
                    q.push({mx,my+1});
                    masu[mx][my+1]=min(masu[mx][my+1],masu[mx][my]+1);
                }

            }
            if(y[mx][my]==0){//うえ
                if(al[mx-1][my]==false){
                    al[mx-1][my]=true;
                    q.push({mx-1,my});
                    masu[mx-1][my]=min(masu[mx-1][my],masu[mx][my]+1);
                }
            }if(y[mx+1][my]==0){//した
                if(al[mx+1][my]==false){
                    al[mx+1][my]=true;
                    q.push({mx+1,my});
                    masu[mx+1][my]=min(masu[mx+1][my],masu[mx][my]+1);
                }
            }
        }

//        rep(i,h){
//            rep(j,w){
//                cout<<masu[i][j];
//            }
//            cout<<endl;
//        }

        if(masu[h-1][w-1]==INF){
            cout<<0<<endl;
        }else{
            cout<<masu[h-1][w-1]<<endl;
        }

    }



    return 0;
}