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 <cstdio>
#include <cstdlib>
#define BUFFER_SIZE 1024

int bfs(int sx,int sy);
const int dx[] = {1, 0, -1, 0}, dy[] = {0, 1, 0, -1};

struct queue {
    int buffer[BUFFER_SIZE];
    int head;
    int tail;
};

void init(struct queue *q)
{
    q->head = 0;
    q->tail = -1;
}

void enqueue(struct queue *q, int x)
{
    if (q->head == q->tail) {
        fprintf(stderr, "queue is full\n");
        exit(1);
    }

    q->buffer[q->head] = x;
    q->head = (q->head + 1) % BUFFER_SIZE;
}

int dequeue(struct queue *q)
{
    int t = (q->tail + 1) % BUFFER_SIZE;
    if (q->head == t) {
        fprintf(stderr, "queue is empty\n");
        exit(1);
    }

    q->tail = t;
    return q->buffer[q->tail];
}


int map_d[32][32];
int map_a[32][32];
int map_b[32][32];
int w,h;

bool isOK(int sx,int sy,int nx,int ny){

  if(ny<0 || nx<0)return false;
  if(sx==nx){
    if(sy<ny){
      if(map_a[sx][sy]==0)return true;
    }
    else if(sy>ny){
      if(map_a[sx][ny]==0)return true;
    }
  }
  else{
    if(sx<nx){
      if(map_b[sx][sy]==0)return true;
    }
    else{
      if(map_b[nx][sy]==0)return true;
    }
  }
  return false;
}
//---->x
//|
//|
//y
int main(){

 
  for(;;){
    
    for(int i=0;i<32;i++){
      for(int j=0;j<32;j++){
	map_d[i][j]=100000;
	map_a[i][j]=1;
	map_b[i][j]=1;
      }
    }
    map_d[0][0]=0;
     

    scanf("%d %d",&w,&h);
    if(w==0)return 0;
    //??\???
    for(int i=0;i<h-1;i++){
      for(int j=0;j<w-1;j++){scanf("%d",&map_a[i][j]);}
      for(int j=0;j<w;j++){scanf("%d",&map_b[i][j]);}
    }
    for(int j=0;j<w-1;j++){scanf("%d",&map_a[h-1][j]);}

    bfs(0,0);

    if(map_d[h-1][w-1]=100000)
      printf("0\n");
    else
      printf("%d\n",map_d[h-1][w-1]+1);
    

  }

}


int bfs(int sx,int sy){
  struct queue q;
  
  init(&q);
  enqueue(&q,sx);
  enqueue(&q,sy);

  
  while (q.head != (q.tail + 1) % BUFFER_SIZE) {

    int x,y;
    
    x=dequeue(&q);
    y=dequeue(&q);
    if(x==w-1 && y == h-1)return 0;
      
    for(int i=0;i<4;i++){
      int nx = x+dx[i],ny=y+dy[i];
      if(!isOK(x,y,nx,ny) || map_d[nx][ny]!=100000){continue;}
      if(map_d[nx][ny]>map_d[x][y]+1)map_d[nx][ny]=map_d[x][y]+1;
      enqueue(&q,nx);
      enqueue(&q,ny);
    }
  }

}