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 <iostream>
#include <vector>
#include <queue>
using namespace std;

const int di[4] = {0,  1,  0, -1};
const int dj[4] = {1,  0, -1,  0};

bool on_grid(int i, int j, int r, int c)
{
    return (i >= 0 && i < r && j >= 0 && j < c);
}

bool canpass(pair<int, int> from, pair<int, int> to, vector< vector<bool> >& wh, vector< vector<bool> >& wv)
{
    // horizontal move
    if (from.first == to.first)
    {
        // move left
        if (from.second > to.second)
        {
            return !wh[from.first][to.second];
        }
        // move right
        else if (from.second < to.second)
        {
            return !wh[from.first][from.second];
        }
        else return false;
    }
    // vertical move
    else if (from.second == to.second)
    {
        // move up
        if (from.first > to.first)
        {
            return !wv[to.first][from.second];
        }
        // move down
        else if (from.first < to.first)
        {
            return !wv[from.first][from.second];
        }
        else return false;
    }
    else return false;
}

int main()
{
    while (true)
    {
        int w, h; cin >> w >> h;
        if (w == 0 && h == 0) break;
        vector< vector<bool> > wh(h, vector<bool>(w - 1, false));
        vector< vector<bool> > wv(h - 1, vector<bool>(w, false));
        for (int i = 0; i < 2 * h - 1; i++)
        {
            // holizontal wall
            if (i % 2 == 0)
            {
                for (int j = 0; j < w - 1; j++)
                {
                    int c; cin >> c;
                    wh[i/2][j] = c == 1 ? true : false;
                }
            }
            // vertical wall
            else
            {
                for (int j = 0; j < w; j++)
                {
                    int c; cin >> c;
                    wv[i/2][j] = c == 1 ? true : false;
                }
            }
        }
        queue< pair<int, int> > q;
        q.push(pair<int, int>(0, 0));
        vector< vector<bool> > seen(h, vector<bool>(w, false));
        seen[0][0] = true;
        int cnt = 0;
        bool success = false;
        while (!q.empty())
        {
            queue< pair<int, int> > qt;
            while (!q.empty())
            {
                qt.push(q.front()); q.pop();
            }
            while (!qt.empty())
            {
                pair<int, int> now = qt.front(); qt.pop();
                for (int i = 0; i < 4; i++)
                {
                    if (on_grid(now.first+di[i], now.second+dj[i], h, w)
                    && seen[now.first+di[i]][now.second+dj[i]] == false
                    && canpass( now, 
                                pair<int, int>(now.first+di[i], now.second+dj[i]),
                                wh, wv ))
                    {
                        seen[now.first+di[i]][now.second+dj[i]] = true;
                        q.push(pair<int, int>(now.first+di[i], now.second+dj[i]));
                    }
                }
            }
            cnt++;
            if (seen[h-1][w-1] == true) { success = true; break; }
        }
        if (success) cout << cnt + 1 << endl;
        else cout << 0 << endl;
    }
    return 0;
}