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 <bits/stdc++.h>

using namespace std;

#define MAX 35
#define INF (1<<29)
typedef pair<int, int> pii;

int main()
{
    int W, H, x;
    while (cin >> W >> H, W) {
        bool wall[MAX][MAX][4];
        for (int i = 0; i < 2*H-1; i++) {
            for (int j = 0; j < W - !(i&1); j++) {
                cin >> x;
                if (!(i & 1)) {
                    wall[i/2][j][2] = wall[i/2][j+1][0] = x;
                } else {
                    wall[(i-1)/2][j][3] = wall[i/2][j][1] = x;
                }
            }
        }

        queue<pii> que;
        que.push(pii(0, 0));

        vector<vector<int>> d(H, vector<int>(W, INF));
        d[0][0] = 0;

        const int dx[] = {-1, 0, 1, 0};
        const int dy[] = {0, -1, 0, 1};

        bool reachable = 0;
        
        while (!que.empty()) {
            pii p = que.front(); que.pop();
            int x = p.first, y = p.second;

            if (x == W-1 && y == H-1) {
                cout << d[y][x] + 1 << endl;
                reachable = 1;
                break;
            }
            
            for (int i = 0; i < 4; i++) {
                int nx = x + dx[i];
                int ny = y + dy[i];
                if (0 <= nx && nx < W && 0 <= ny && ny < H &&
                    !wall[y][x][i] &&
                    d[y][x] + 1 < d[ny][nx]) {
                    d[ny][nx] = d[y][x] + 1;
                    que.push(pii(nx, ny));
                }
            }
        }

        if (!reachable) {
            cout << 0 << endl;
        }
    }
    return 0;
}

C++: #include <iostream>
#include <queue>
#include <cstring>
#include <complex>
#define H (30+2)*2
#define W (30+2)*2
#define ARI 1
#define NASI 0
using namespace std;

typedef struct {
  int x,y, n;
} P;

int w,h;
int m[H][W];

void pr(){
  for( int i=0;i<=2*h;i++ ){
    for( int j=0;j<=2*w;j++ )	
      if( m[i][j]==NASI ) cout << " ";
      else                cout << "#";
    cout << endl;
  }
  cout << endl;
}

int main(){
  P p, pn;
  queue<P> q;
  while( cin >> w >> h && (w||h) ){

    memset( m, NASI, sizeof(m) );

    for( int i=0,lenH=2*h;i<=lenH;i++ ){
      m[i][0]   = ARI;
      m[i][2*w] = ARI;
      if( i==0 || i==lenH ){
	for( int j=1,lenW=2*w;j<lenW;j++ )
	  m[i][j] = ARI;
      } else if( i%2==1 ){
	for( int j=2,lenW=2*w;j<lenW;j+=2 )
	  cin >> m[i][j];
      } else {
	for( int j=1,lenW=2*w;j<lenW;j+=2 )
	  cin >> m[i][j];
      }
    }

    //    pr();

    int ansX = 0;
    while( q.size()>0 ) q.pop();
    p.x=1; p.y=1; p.n=1;
    q.push( p );
    while( q.size()>0 ){
      p = q.front(); q.pop();
      int i=p.y, j=p.x;

      if( m[i][j]==ARI )
	continue;
      /*
      pr();
      cout << i << "," << j << ","<< p.n << endl;      
      */
      if( i==2*h-1 && j==2*w-1 ){
	ansX = p.n;  break;
      }
      m[i][j]=ARI;
      p.n++;
      if( m[i+1][j]==NASI ){
	pn=p; pn.y+=2; q.push( pn );
      }
      if( m[i-1][j]==NASI ){
	pn=p; pn.y-=2; q.push( pn );
      }
      if( m[i][j+1]==NASI ){
	pn=p; pn.x+=2; q.push( pn );
      }
      if( m[i][j-1]==NASI ){
	pn=p; pn.x-=2; q.push( pn );
      }
    }
    cout << ansX << endl;

    //    break;
  }
  return 0;
}