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 std::cin;
using std::cout;
using std::endl;
using std::vector;

struct data_t {
	bool up;
	bool down;
	bool left;
	bool right;
	bool check;
};

int main(void) {
	int w,h;
	cin >> w >> h;

	while( w != 0 || h != 0 ) {

		vector < vector<data_t> > maze(h+2, vector<data_t>(w+2));
		for (int i = 0; i < h+2; i++) {
			for (int j = 0; j < w+2; j++) {
				if (i==0||i==h+1||j==0||j==w+1) {
					maze[i][j].up = false;
					maze[i][j].down = false;
					maze[i][j].left = false;
					maze[i][j].right = false;
					maze[i][j].check= true;
				}
				else {
					maze[i][j].up = true;
					maze[i][j].down = true;
					maze[i][j].left = true;
					maze[i][j].right = true;
					maze[i][j].check= false;

					if ( i == 1 ) {
						maze[i][j].up = false;
					}
					if ( j == 1 ) {
						maze[i][j].left = false;
					}
					if ( i == h ) {
						maze[i][j].down = false;
					}
					if ( j == w ) {
						maze[i][j].right = false;
					}
				}
			}
		}

		bool mode_w = true;
		int temp;
		int count = 1;
		int l = 1;
		for (int i = 0; i < ( ((w-1)*h)+(w*(h-1)) ); i++) {
			cin >> temp;
			if (mode_w) {
				if (temp == 1) {
					maze[l][count].right = false;
					maze[l][count+1].left = false;
				}
				count++;
				if (count == w) {
					count = 1;
					mode_w = false;
				}
			}
			else {
				if (temp == 1) {
					maze[l][count].down = false;
					maze[l+1][count].up = false;
				}
				count++;
				if (count == w+1) {
					count = 1;
					mode_w = true;
					l++;
				}
			}
		}

		std::queue<int> qh,qw,d;
		qh.push(1);
		qw.push(1);
		d.push(1);
		int hn,wn;
		int spl;
		int dn = 1;
		int count_d = 0;
		bool goal = false;

		while ( !(goal) && !(qw.empty()) ) {
			hn = qh.front();
			wn = qw.front();
			dn = d.front();
			qh.pop();
			qw.pop();
			d.pop();
			count_d++;

			maze[hn][wn].check = true;

			if ( hn == h && wn == w ) {
				cout << dn << endl;
				goal = true;
			}

			if ( maze[hn][wn].up && !(maze[hn-1][wn].check) ) {
				qh.push(hn-1);
				qw.push(wn);
				d.push(dn+1);
				maze[hn-1][wn].check = true;
			}
			if ( maze[hn][wn].down && !(maze[hn+1][wn].check) ) {
				qh.push(hn+1);
				qw.push(wn);
				d.push(dn+1);
				maze[hn+1][wn].check = true;
			}
			if ( maze[hn][wn].left && !(maze[hn][wn-1].check) ) {
				qh.push(hn);
				qw.push(wn-1);
				d.push(dn+1);
				maze[hn][wn-1].check = true;
			}
			if ( maze[hn][wn].right && !(maze[hn][wn+1].check) ) {
				qh.push(hn);
				qw.push(wn+1);
				d.push(dn+1);
				maze[hn][wn+1].check = true;
			}
		}

		if (!(goal)) {
			cout << 0 << endl;
		}

		cin >> w >> h;
	}

	return 0;
}