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++: //
//  main.cpp
//  AOJ1166
//
//  Created by aki33524 on 2014/07/06.
//  Copyright (c) 2014年 aki33524. All rights reserved.
//

#include <iostream>
#include <queue>
#include <vector>
#include <string.h>
using namespace std;

typedef pair<int, int> P;
const int INF = 1e8;
int dh[] = {1, 0, -1, 0};
int dw[] = {0, 1, 0, -1};

int W, H;
int d[50][50];
int maze[50][50];

void solve(){
    queue<P> que;
    for(int h=0; h<H; h++)
        for(int w=0; w<W; w++)
            d[h][w] = INF;
    
    que.push(P(0, 0));
    d[0][0] = 1;
    
    while(!que.empty()){
        P p = que.front(); que.pop();
        for(int i=0; i<4; i++){
            int nh = p.first + dh[i];
            int nw = p.second + dw[i];
            if(0<=nh&&nh<H && 0<=nw&&nw<W && !(maze[p.first][p.second]&(1<<i)) && d[nh][nw]==INF){
                que.push(P(nh, nw));
                d[nh][nw] = d[p.first][p.second] + 1;
            }
        }
    }
    cout << (d[H-1][W-1]==INF ? 0 : d[H-1][W-1]) << endl;
}

int main(int argc, const char * argv[]){
    while(cin>>W>>H, W|H){
        memset(maze, 0, sizeof(maze));
        
        for(int h=0; h<H*2-1; h++){
            if(h%2 == 0){
                for(int w=0; w<W-1; w++){
                    int a;
                    cin >> a;
                    if(a){
                        maze[h/2][w] |= (1<<1);
                        maze[h/2][w+1] |= (1<<3);
                    }
                }
            }else{
                for(int w=0; w<W; w++){
                    int a;
                    cin >> a;
                    if(a){
                        maze[h/2][w] |= (1<<0);
                        maze[h/2+1][w] |= (1<<2);
                    }
                }
            }
        }
        solve();
    }
    return 0;
}

C++: #include <bits/stdc++.h>
#include <map>
#define chmin(a, b) ((a)=min((a), (b)))
#define chmax(a, b) ((a)=max((a), (b)))
#define fs first
#define sc second
#define eb emplace_back
using namespace std;
 
typedef long long ll;
typedef pair<int, int> P;
typedef tuple<int, int, int> T;
 
const ll MOD=1e9+7;
const ll INF=1e18;
 
int dx[]={1, -1, 0, 0};
int dy[]={0, 0, 1, -1};


int ans[35][35];
int wall[70][70];
int w,h;

bool check(int y1,int x1,int y2,int x2){
    if(min(min(x1,y1),min(x2,y2)) < 0 || max(x1,x2) >= w || max(y1,y2) >= h) return false;
    if(y1 == y2){
        if(wall[y1*2][min(x1,x2)] == 1){
            return false;
        }else{
            return true;
        }
    }else{
        if(wall[min(y1,y2)*2+1][x1] == 1){
            return false;
        }else{
            return true;
        }
    }
}

int main(){
    
    while(true){
        cin >> w >> h;
        if(w + h == 0) break;
        for(int i = 0;i < h;i++){
            for(int j = 0;j < w;j++){
                ans[i][j] = -1;
            }
        }
        for(int i = 0;i < 2*h-1;i++){
            for(int j = 0;j < w - 1 + i%2;j++){
                cin >> wall[i][j];
            }
        }
        ans[0][0] = 1;
        queue<P> que;
        que.push(P(0,0));
        int flag = 0;
        while(!que.empty()){
            P q = que.front(); que.pop();
            if(q.fs == h-1 && q.sc == w-1){
                flag = 1;
                cout << ans[q.fs][q.sc] << endl;
                break;
            }
            for(int i = 0;i < 4;i++){
                if( check(q.fs,q.sc,q.fs+dy[i],q.sc+dx[i]) == true && ans[q.fs+dy[i]][q.sc+dx[i]]==-1){
                    ans[q.fs+dy[i]][q.sc+dx[i]] = ans[q.fs][q.sc] + 1;
                    que.push(P(q.fs+dy[i],q.sc+dx[i]));
                }
            }
            
        }
        if(flag == 0){
            cout << 0 << endl;
        }
    }
}