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 <queue>
#include <iostream>
#include <fstream>
#include <algorithm>
#define rep(i, n) for(int i=0; i<(n); ++i)

using namespace std;

//--global--//

struct wall{
    bool t, b, r, l;
};

//----------//

int main(int argc, const char * argv[]) {
    //提出時、消す----//
    //--------------//

    while(1){
        int w, h;
        cin >> w >> h;
        if(w == 0 && h == 0)break;
        wall wall[35][35];
        bool res[35][35];
        rep(i, 35){
            fill(res[i], res[i]+35, false);
        }

        rep(i, h){
            rep(j, w){
                wall[i][j].t = false;
                wall[i][j].b = false;
                wall[i][j].l = false;
                wall[i][j].r = false;
                if(i == 0 ){
                    wall[i][j].t = true;
                }
                if(i == h-1){
                    wall[i][j].b = true;
                }
                if(j == 0){
                    wall[i][j].l = true;
                }
                if(j == w-1){
                    wall[i][j].r = true;
                }
            }
        }

        rep(i, h*2-1){
            if(i % 2== 0){
                rep(j, w-1){
                    int a;
                    cin >> a;
                    if(a == 1){
                        wall[i/2][j].r = true;
                        wall[i/2][j+1].l = true;
                    }
                }
            }
            else{
                rep(j, w){
                    int a;
                    cin >> a;
                    if(a == 1){
                        wall[i/2][j].b = true;
                        wall[i/2+1][j].t = true;
                    }
                }
            }
        }

        //cout << wall[0][0].t << endl;

        queue<pair<int, int> > q2;
        q2.push(make_pair(0, 0));
        int cnt = 0;
        bool ok = false;
        res[0][0] = true;
        while(1){

            queue<pair<int, int> > q;
            q = q2;
            while(!q2.empty()){
                q2.pop();
            }
            while(!q.empty()){
                pair<int, int> f = q.front(); q.pop();
                // t b 
                int x = f.first;
                int y = f.second;
                //cout << x << ", " << y << endl;
                if(x == w-1 && y == h-1){
                    ok = true;
                    break;
                }
                if(!wall[y][x].t) {
                    if(!res[y-1][x]){
                        q2.push(make_pair(x, y-1));
                        res[y-1][x] = true;
                    }
                }
                if(!wall[y][x].b) {
                    if(!res[y+1][x]){
                        q2.push(make_pair(x, y+1));
                        res[y+1][x] = true;
                    }
                }
                if(!wall[y][x].l) {
                    if(!res[y][x-1]){
                        q2.push(make_pair(x-1, y));
                        res[y][x-1] = true;
                    }
                }
                if(!wall[y][x].r) {
                    if(!res[y][x+1]){
                        q2.push(make_pair(x+1, y));
                        res[y][x+1] = true;
                    }
                }
            }
            cnt++;
            if(ok)break;
            if(q2.empty()){
                cout << 0 << endl;
                ok = false;
                break;
            }
        }

        if(ok)
            cout << cnt << endl;

    }
    
    return 0;
}