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;

#ifdef LOCAL
#include "../dump.hpp"
#else
#define dump(...)
#endif

#define rep(i,n) for(ll i=0,i##_cond=(n);i<i##_cond;i++)
#define FOR(i,a,b) for(ll i=(a),i##_cond=(b);i<i##_cond;i++)
#define ROF(i,a,b) for(ll i=(a)-1,i##_cond=(b);i>=i##_cond;i--)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend() //sortで大きい順
#define UNIQUE(v) v.erase(unique(all(v)),v.end())
#define SUM(a) accumulate(all(a),0)
#define sz(x) ((ll)(x).size())
#define pb push_back
#define fst first
#define snd second
#define mp make_pair

typedef long long ll;
typedef vector<ll> vi;
typedef vector<vi> vvi;
typedef vector<string> vs;
typedef pair<ll,ll> pii;

const ll inf = 1ll<<62;
const ll mod = 1e9+7;

#define int ll

main()
{
  vi dx = {1, 0, -1, 0}, dy = {0, 1, 0, -1};
  while(1){
    int h,w; cin >> w >> h;
    if(h == 0) break;

    vvi d(h,vi(w,-1)), in(2*h-1,vi(w));
    rep(i,sz(in)){
      if(i & 1) rep(j,w) cin >> in[i][j];
      else rep(j,w-1) cin >> in[i][j];
    }

    queue<pii> q;
    q.push(pii(0,0));
    d[0][0] = 0;

    while(not q.empty()){
      pii p = q.front();
      q.pop();

      rep(i,4){
	int nx = p.fst + dx[i], ny = p.snd + dy[i];
	if(0 <= nx and nx < h and 0 <= ny and ny < w and d[nx][ny] == -1){
	  dump(nx,ny);
	  bool f = true; // 移動できるかどうか
	  
	  if(p.fst == nx and in[2 * nx][min(p.snd, ny)] == 1) // y方向
	    f = false;
	  else if(p.snd == ny and in[p.fst + nx][ny] == 1) // x方向
	    f = false;
	    
	  if(f){
	    d[nx][ny] = d[p.fst][p.snd] + 1;
	    q.push(pii(nx,ny));
	  }
	}
      }
    }
    dump(d);
    cout << d[h-1][w-1] + 1 << endl;
  }
}

C++: #include <cstdio>
#include <iostream>
#include <string>
#include <queue>
using namespace std;

int W,H,w[33][33],h[33][33];

struct point{
  int x,y;
};

int bfs(){
  point u,v;
  queue<point> Q;
  int D[37][37],ny,nx;
  int dy[4] = {0,-1,0,1};
  int dx[4] = {1,0,-1,0};

  for(int i=0;i<H;i++){
    for(int j=0;j<W;j++) D[i][j] = 10000;
  }

  u.y = u.x = 0;
  D[u.y][u.x] = 1;
  Q.push(u);

  while(!Q.empty()){
    u = Q.front();
    Q.pop();
    if(u.y == H-1 && u.x == W-1) return D[u.y][u.x];

    for(int r=0; r<4; r++){
      nx = u.x + dx[r];
      ny = u.y + dy[r];
      if(nx < 0 || ny < 0 || nx >= W || ny >= H)  continue;
      if(D[ny][nx] != 10000) continue;
      if(r == 0 && w[u.y][u.x] == 1) continue;
      if(r == 1 && h[ny][u.x] == 1) continue;
      if(r == 2 && w[u.y][nx] == 1) continue;
      if(r == 3 && h[u.y][u.x] == 1) continue;
      D[ny][nx] = D[u.y][u.x] + 1;
      v.x = nx;
      v.y = ny;
      Q.push(v); 
    }
  }
  return 0;
}    

int main(){
  int i,j;
  while(1){
    cin >> W >> H;
    if(W == 0 && H == 0) break;

    for(i=0;i<W-1;i++){
      cin >> w[0][i];
    }

    for(i=1;i<H;i++){
      for(j=0;j<W;j++){
	cin >> h[i-1][j];
      }
      for(j=0;j<W-1;j++){
	cin >> w[i][j];
      }
    }
    cout << bfs() << endl;

  }

  return 0;
}