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 <algorithm>
#include <utility>
#include <cstdio>
#include <cstdlib>
#include <cstring>

using namespace std;
#define REP(i,b,n) for(int i=b;i<n;i++)
#define rep(i,n) REP(i,0,n)
int w,h;
int maze[40][40];
int d[2][4]={{1,0,-1,0},{0,1,0,-1}};

typedef pair<pair<int,int>, int> State;

void show(){
	rep(i,h*2-1){
		rep(j,w*2-1){
			cout<<maze[i][j];
		}
		cout<<endl;
	}
	cout<<endl;
}
void solve(){
	queue<State> q;
	q.push(State(make_pair<int,int>(0,0),1));
	pair<int,int> goal(2*w-2,2*h-2);
	while(!q.empty()){
		State cur=q.front();q.pop();
		if(goal == cur.first){
			cout<<cur.second<<endl;
			return ;
		}
		for(int i=0;i<4;i++){
			int nx=cur.first.first+d[0][i];//x
			int ny=cur.first.second+d[1][i];//y
			if(nx<0||ny<0||nx>goal.first||ny>goal.second||maze[ny][nx]==1)continue;
			nx+=d[0][i];
			ny+=d[1][i];
			if(nx<0||ny<0||nx>goal.first||ny>goal.second||maze[ny][nx]==1)continue;
			maze[ny][nx]=1;
			q.push(State(make_pair(nx,ny),cur.second+1));
		}
	}
	
	cout<<0<<endl;
}

int main(){
	while(cin>>w>>h&&(w||h)){
		rep(i,40)rep(j,40)maze[i][j]=0;
		rep(i,h*2-1){
			if(i%2){
				rep(j,w){
					cin>>maze[i][j*2];
				}
			}
			else {
				rep(j,w-1){
					cin>>maze[i][j*2+1];
				}
			}
		}
		solve();
	}
	return 0;
}

C++: #include <iostream>
using namespace std;
int main(int argc, char *argv[])
{
  for(;;) {
    auto solve = [](){
      int n, m;
      cin >> n >> m;
      if(n==0 && m==0) exit(0);
      bool maze[m][n][4];
      int di [] = {0,0,1,-1};
      int dj [] = {1,-1,0,0};
      for(int i = 0; i < m*2-1; i++) {
        if(i % 2) { // side walls
          for(int j = 0; j < n; j++) {
            int k;
            cin >> k;
            int ii = i/2;
            maze[ii][j][2]   = k==1;    // to down
            maze[ii+1][j][3] = k==1;    // to top
          }
        } else { // vert walls
          for(int j = 0; j < n - 1; j++) {
            int k;
            cin >> k;
            int ii = i/2;
            maze[ii][j][0]   = k==1;    // to right
            maze[ii][j+1][1] = k==1;    // to left
          }
        }
      }
      int que_body[n*m];
      int nextque_body[n*m];
      int *que = que_body;
      int *nextque = nextque_body;
      int sp = 0;
      int nextsp = 0;
      int cnt = 0;
      bool visited[n*m];
      for(int i = 0; i < n*m; i++) {
        visited[i] = 0;
      }
      que[sp++] = 0;
      visited[0] = true;
      while(sp > 0) {
        cnt++;
        for(int k = 0; k < sp; k++) {
          int q = que[k];
          if(q == m*n-1) return cnt;
          int i = q / n;
          int j = q % n;
          //cout << cnt << " visiting " << i << ","<<j << endl;
          for(int o = 0; o < 4; o++) {
            int i2 = i + di[o];
            int j2 = j + dj[o];
            if(i2 >= 0 && j2 >= 0 && i2 < m && j2 < n && !maze[i][j][o]) {
              int nq = i2 * n + j2;
              if(!visited[nq]) {
                visited[nq] = true;
                nextque[nextsp++] = nq;
                //cout << cnt << " pushing " << i2 << ","<<j2 << endl;
              }
            }
          }
        }
        sp = nextsp;
        int *p = que;
        que = nextque;
        nextque = p;
        nextsp = 0;
      }
      return 0;
    };
    cout << solve() << endl;
  }
  return 0;
}