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 mp make_pair
#define fi first
#define se second
#define FOR(i,a,b) for (int i=(a);i<(b);i++)
vector<vector<bool>> visit(30,vector<bool> (30,false));
int graph[30][30][30][30];


int bfs(int a,int b)
{
    int dis[30][30];
    bool visit[30][30];
    FOR(i,0,30) FOR(j,0,30)
    {
        visit[i][j]=false;
        dis[i][j]=-1;
    }
    dis[0][0]=0;
    visit[0][0]=true;
    queue<pair<int,int>> que;
    que.push(mp(0,0));
    int u,v,x,y;
    while (!que.empty())
    {
        u=que.front().fi;
        v=que.front().se;
        que.pop();
        vector<pair<int,int>> around={mp(u-1,v),mp(u+1,v),mp(u,v-1),mp(u,v+1)};
        for (int i=0;i<4;i++)
        {
            x=around[i].fi;
            y=around[i].se;
            if (0<=x && x<=a && 0<= y&& y <= b)
            {
                //cout << x << " " << y << endl;
                //cout <<graph[u][v][x][y] <<!visit[x][y]<< endl;
                if (graph[u][v][x][y] && !visit[x][y])
                {
                    dis[x][y]=dis[u][v]+1;
                    visit[x][y]=true;
                    que.push(mp(x,y));
                    //cout << x << " "<<y << endl;
                }
            }
        }
    }
    return dis[a][b]+1;
}

int main()
{
    vector<int> ans;
    int h,w;
    while (true)
    {
        cin >> h >> w;
        if (h==0 && w==0) break;
        int a;
        FOR(i,0,30) FOR(j,0,30) FOR(k,0,30) FOR (l,0,30) graph[i][j][k][l]=0;
        for (int i=0;i<2*w-1;i++)
        {
            if (i%2==0)
            {
                for (int j=0;j<h-1;j++)
                {
                    cin >> a;
                    if (a==0) 
                    {
                        graph[i/2][j][i/2][j+1]=1;
                        graph[i/2][j+1][i/2][j]=1;
                    }
                    else 
                    {
                        graph[i/2][j][i/2][j+1]=0;
                        graph[i/2][j+1][i/2][j]=0;
                    }
                }
            }
            else
            {
                for (int j=0;j<h;j++)
                {
                    cin >> a;
                    if (a==0)
                    {
                        graph[i/2][j][i/2+1][j]=1;
                        graph[i/2+1][j][i/2][j]=1;
                    } 
                    else 
                    {
                        graph[i/2][j][i/2+1][j]=0;
                        graph[i/2+1][j][i/2][j]=0;
                    }
                }
            }
        }
        ans.push_back(bfs(w-1,h-1));
    }
    for (int i=0;i<ans.size();i++) cout << ans[i] << endl;
    return 0;
}