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;
int dx[] = {-1, 1, 0, 0};
int dy[] = {0, 0, -1, 1};
const int INF = 100000;
typedef pair<int, int> P;
int w, h;
int ny,nx;
int main()
{
    while (cin >> w >> h)
    {
        int dis[h][w];
        bool wall[2][h][w];
        if (w == 0 && h == 0)
            return 0;
        for (int i = 0; i < h; i++)
        {
            for (int j = 0; j < w; j++)
            {
                dis[i][j] = INF;
            }
        }
        for (int i = 0; i < 2 * h - 1; i++)
        {
            //横
            if (i % 2 == 0)
            {
                for (int j = 0; j < w - 1; j++)
                {
                    cin >> wall[0][i / 2][j];
                }
            }
            //縦
            else
            {
                for (int j = 0; j < w; j++)
                {
                    cin >> wall[1][i / 2][j];
                }
            }
        }
        dis[0][0] = 1;
        queue<P> que;
        que.push(P(0, 0));
        while (!que.empty())
        {
            P p = que.front();
            que.pop();
            ny = p.first;
            nx = p.second;
            if (ny - 1 >= 0 && wall[1][ny - 1][nx] == 0 && dis[ny-1][nx] == INF)
            {
                dis[ny - 1][nx] = dis[ny][nx] + 1;
                que.push(P(ny - 1, nx));
            }
            if (ny + 1 < h && wall[1][ny][nx] == 0 && dis[ny + 1][nx] == INF)
            {
                dis[ny + 1][nx] = dis[ny][nx] + 1;
                que.push(P(ny + 1, nx));
            }
            if (nx - 1 >= 0 && wall[0][ny][nx - 1] == 0 && dis[ny][nx - 1] == INF)
            {
                dis[ny][nx - 1] = dis[ny][nx] + 1;
                que.push(P(ny, nx - 1));
            }
            if (nx + 1 < w && wall[0][ny][nx] == 0 && dis[ny][nx + 1] == INF)
            {
                dis[ny][nx + 1] = dis[ny][nx] + 1;
                que.push(P(ny, nx + 1));
            }
        }
        if (dis[h - 1][w - 1] == INF)
            cout << 0 << endl;
        else
            cout << dis[h - 1][w - 1] << endl;
    }
}

C++: // AOJ1166  
#include <bits/stdc++.h>
#define endl "\n"
#define _GLIBCXX_DEBUG //配列外参照エラー表示,gcc依存
#define rep(i,n) for(int i=0;i<int(n);i++)
#define SZ(x) ((int)(x).size())
#define all(x) (x).begin(),(x).end()
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ipair;
template <class T>ostream &operator<<(ostream &o,const vector<T>&v)
{o<<"{";for(int i=0;i<(int)v.size();i++)o<<(i>0?", ":"")<<v[i];o<<"}";return o;}
namespace you {
    std::string to_string(char val) {
        return std::string(1, val);
        // return std::string{val};
        // you::to_string(char)
    }
}
vector<int> yy={0,-1,0,1};
vector<int> xx={-1,0,1,0};
int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(12);

    int X,Y;
    while(cin>>X>>Y){
        if(X==0 && Y==0) break;
        vector<vector<int>> tatekabe(Y,vector<int>(X-1));
        vector<vector<int>> yokokabe(Y-1,vector<int>(X));
        rep(i,X-1) cin>>tatekabe[0][i];
        rep(i,Y-1){
            rep(j,X){
                cin>>yokokabe[i][j];
            }
            rep(j,X-1){
                cin>>tatekabe[i+1][j];
            }
        }
        //cout<<tatekabe<<endl;
        //cout<<yokokabe<<endl;
        vector<vector<int>> dis(Y,vector<int>(X,-1));
        dis[0][0]=1;
        queue<ipair> next;
        next.push(ipair(0,0));
        int ans=0;
        while(!next.empty()){
            ipair q=next.front();
            int cy=q.first,cx=q.second;
            next.pop();
            rep(i,4){
                int ny=cy+yy[i],nx=cx+xx[i];
                if(ny<0||Y<=ny||nx<0||X<=nx) continue;
                if(dis[ny][nx]!=-1) continue;
                if(ny==cy){
                    if(tatekabe.at(ny).at(min(nx,cx))==1) continue; //縦の壁がある
                    dis[ny][nx]=dis[cy][cx]+1;
                    next.push(ipair(ny,nx));
                }else if(nx==cx){
                    if(yokokabe.at(min(ny,cy)).at(nx)==1) continue; //横の壁がある
                    dis[ny][nx]=dis[cy][cx]+1;
                    next.push(ipair(ny,nx));
                }
            }
            if(dis[Y-1][X-1]!=-1){
                ans=dis[Y-1][X-1];
                break;
            }
        }
        cout<<ans<<endl;
    }

    return 0;
}