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>
#include <vector>
using namespace std;
int w,h;
char map[100][100];
class Node{
public:
	int x,y;
	int c;
	Node(int _x,int _y,int _c):x(_x),y(_y),c(_c){

	}
};
void show(){
	for(int i=0;i<h*2-1;i++){
		for(int j=0;j<w*2-1;j++)cout<<map[i][j];
		cout<<endl;
	}
	cout<<endl;
}
bool visited[100][100];
int dx[]={1,0,-1,0};
int dy[]={0,-1,0,1};
int bfs(){
	for(int i=0;i<100;i++)fill(visited[i],visited[i]+100,false);
	queue<Node> q;
	q.push(Node(0,0,1));
	visited[0][0]=true;
	int gw=2*w-2;
	int gh=2*h-2;
	while(!q.empty()){
		Node cur=q.front();q.pop();
//		cout<<"("<<cur.x<<","<<cur.y<<")"<<endl;
		map[cur.y][cur.x]='1';
//		show();
		if(cur.x==gw&&cur.y==gh)return cur.c;
		for(int i=0;i<4;i++){
			int nx=cur.x+dx[i];
			int ny=cur.y+dy[i];
//			cout<<"next("<<nx<<","<<ny<<")"<<endl;
			if(nx<0||ny<0||nx>gw||ny>gh||map[ny][nx]=='1'||map[ny+dy[i]][nx+dx[i]]=='1')continue;
			visited[ny+dy[i]][nx+dx[i]]=true;
			q.push(Node(nx+dx[i],ny+dy[i],cur.c+1));
		}
	}
	return 0;
}
void solve(){
	cout<<bfs()<<endl;
}
int main(){
	while(cin>>w>>h&&(w||h)){
		for(int i=0;i<100;i++)for(int j=0;j<100;j++)map[i][j]='0';
		int hline=h*2-1;
		for(int i=0;i<hline;i++){
			if(i%2){
				for(int j=0;j<w;j++)cin>>map[i][2*j];
			}
			else {
				for(int j=0;j<w-1;j++)cin>>map[i][1+2*j];

			}
		}
//		show();
		solve();
	}
	return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<queue>
using namespace std;
int n,m;
string s[99];
int d[99][99];
int dx[]={0,1,0,-1},dy[]={1,0,-1,0};
main()
{
	while(cin>>m>>n,n)
	{
		for(int i=0;i<2*n-1;i++)for(int j=0;j<2*m-1;j++)d[i][j]=1e9;
		cin.ignore();
		for(int i=0;i<2*n-1;i++)getline(cin,s[i]);
		d[0][0]=1;
		queue<pair<int,int> >P;
		P.push(make_pair(0,0));
		while(!P.empty())
		{
			int x=P.front().first,y=P.front().second;P.pop();
			for(int r=0;r<4;r++)
			{
				int tx=x+dx[r],ty=y+dy[r];
				if(tx<0||ty<0||tx>=2*n||ty>=2*m||s[tx][ty]=='1')continue;
				tx+=dx[r],ty+=dy[r];
				if(d[tx][ty]<1e9)continue;
				d[tx][ty]=d[x][y]+1;
				P.push(make_pair(tx,ty));
			}
		}
		cout<<(d[2*n-2][2*m-2]<1e9?d[2*n-2][2*m-2]:0)<<endl;
	}
}

C++: #include<bits/stdc++.h>
using namespace std;
#define lp(i,n) for(int i=0;i<n;i++)
#define lpin(a,i,n) for(int i=0;i<n;i++){cin>>a[i];}

int a[100][100],b[100][100],check[100][100],ans;

void calc(int noww,int nowh,int gw,int gh,int w){
  if(noww==gw && nowh==gh){
    if(ans>w) ans=w;
    return;
  }
  if(check[nowh][noww]==0) check[nowh][noww]=w;
  else {
    if(check[nowh][noww]>w) check[nowh][noww]=w;
    else return;
  }
  if(noww!=0){
    if(a[nowh][noww-1]==0) calc(noww-1,nowh,gw,gh,w++);
  }
  if(nowh!=0){
    if(b[nowh-1][noww]==0) calc(noww,nowh-1,gw,gh,w++);
  }
  if(noww!=gw){
    if(a[nowh][noww]==0) calc(noww+1,nowh,gw,gh,w++);
  }
  if(nowh!=gh){
    if(b[nowh][noww]==0) calc(noww,nowh+1,gw,gh,w++);
  }
}

int main(){
  while(1){
    int w,h;
    cin>>w>>h;
    if(w==0&&h==0) break;
    lp(i,h*2-1){
      lp(j,w){
	if(i%2==0){
	  if(j==w-1) continue;
	  cin>>a[i/2][j];
	}
	else cin>>b[i/2][j];
      }
    }
    lp(i,100){
      lp(j,100){
	check[i][j]=0;
      }
    }
    ans=1000000;
    calc(0,0,w-1,h-1,1);
    if(ans==1000000) ans=0;
    cout<<ans<<endl;
  }
  return 0;
}