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<queue>
using namespace std;

#define MAX 99999999

int main()
{
  int w,h;
  for(;cin>>w>>h,w;)
    {
      int maps[h][w];
      for(int i=0;i<h;i++)
        for(int j=0;j<w;j++)
          maps[i][j]=MAX;
      bool tate[h][w-1];
      bool yoko[h-1][w];
      for(int i=0;i<h;i++)
        {
          for(int j=0;j<w-1;j++)
            {
              cin>>tate[i][j];
            }
          if(i!=h-1)
            {
              for(int j=0;j<w;j++)
                {
                  cin>>yoko[i][j];
                }
            }
        }
      maps[0][0]=1;
      queue<pair<int,int> > qu;
      int ans=0;
      qu.push(make_pair(0,0));
      const int dx[]={0,0,-1,1};
      const int dy[]={-1,1,0,0};

      while(!qu.empty())
        {
          int x=qu.front().first;
          int y=qu.front().second;
          qu.pop();
          //cerr<<"[queue]:"<<x<<","<<y<<endl;
          if(x==h-1 && y==w-1)
            {
              ans=maps[x][y];
              break;
            }
          for(int i=0;i<4;i++)
            {
              //cerr<<"i:"<<i<<endl;

              if(x+dx[i]>=0 && y+dy[i]>=0 &&
                 x+dx[i]<h && y+dy[i]<w &&
                 maps[x][y]+1<maps[x+dx[i]][y+dy[i]])
                {
                  //cerr<<tate[x][y-1]<<" "<<tate[x][y]<<" "<<yoko[x-1][y]<<" "<<yoko[x][y]<<endl;

                  if(i==0 && tate[x][y-1]==0)
                    {
                      qu.push(make_pair(x+dx[i], y+dy[i]));
                      maps[x+dx[i]][y+dy[i]] = maps[x][y]+1;
                    }
                  if(i==1 && tate[x][y]==0)
                    {
                      //cerr<<"[1]"<<endl;

                      qu.push(make_pair(x+dx[i], y+dy[i]));
                      maps[x+dx[i]][y+dy[i]]= maps[x][y]+1;
                    }
                  if(i==2 && yoko[x-1][y]==0)
                    {
                      qu.push(make_pair(x+dx[i], y+dy[i]));
                      maps[x+dx[i]][y+dy[i]]= maps[x][y]+1;
                    }
                  if(i==3 && yoko[x][y]==0)
                    {
                      qu.push(make_pair(x+dx[i], y+dy[i]));
                      maps[x+dx[i]][y+dy[i]]= maps[x][y]+1;
                    }
                }

            }

        }
      cout<<ans<<endl;

    }


}

C++: #include <bits/stdc++.h>

using namespace std;

typedef long long int ll;
typedef pair<int,int> P;

#define rep(i,n) for(int i=0;i<(n);++i)
#define repi(i,a,b) for(int i=int(a);i<(b);i++)
#define all(x) x.begin(),x.end()

const ll mod = 1e9+7;
const ll INF = 1e9;

ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};

bool valid(int lx,int ux,int ly,int uy,int x,int y){
	return (lx<=x&&x<ux&&ly<=y&&y<uy);
}

int solve(int w,int h){
	vector<vector<int>> m(h,vector<int>(w,-1));

	set<P> wall;
	rep(i,2*h-1){
		if(i%2==0){
			rep(j,w-1){
				int x;
				cin>>x;
				if(x==1){
					wall.insert(P(i/2*w+j,i/2*w+j+1));
					wall.insert(P(i/2*w+j+1,i/2*w+j));
				}
			}
		}else{
			rep(j,w){
				int x;
				cin>>x;
				if(x==1){
					wall.insert(P(i/2*w+j,i/2*w+w+j));
					wall.insert(P(i/2*w+w+j,i/2*w+j));
				}
			}
		}
	}

	m[0][0]=1;
	queue<int> que;
	que.push(0);
	while(!que.empty()){
		int pos_h=que.front()/w;
		int pos_w=que.front()%w;
		que.pop();

		rep(i,4){
			if(valid(0,w,0,h,pos_w+dx[i],pos_h+dy[i])){
				if(m[pos_h+dy[i]][pos_w+dx[i]]<0 && wall.count(P(pos_h*w+pos_w,w*(pos_h+dy[i])+pos_w+dx[i]))==0){
					m[pos_h+dy[i]][pos_w+dx[i]] = m[pos_h][pos_w]+1;
					que.push(w*(pos_h+dy[i])+pos_w+dx[i]);
				}
			}
		}
	}

	if(m[h-1][w-1]<0) m[h-1][w-1]=0;

	return m[h-1][w-1];
}


int main()
{
	int h,w;
	while(cin>>w>>h,w!=0&&h!=0){
		cout<<solve(w,h)<<endl;
	}
	return 0;
}