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<stdio.h>
#include<iostream>
#include<math.h>
#include<algorithm>
#include<string>
#include<utility>
#include<queue>
#define pi 3.14159
#define Inf 99999

using namespace std;
typedef std::pair<int, int> mypair;
int w, h, a[59][59];
queue<mypair> qu;
void bfs(int y, int x, int step);

int main(){
	while(1) {
		cin >> w >> h;
		if(w == 0 && h == 0) break;
		for(int i = 0; i < 2*h-1; i++) {
			for(int j = 0; j < 2*w-1; j++) {
				if(i % 2 == 0 && j % 2 == 0) a[i][j] = Inf;
				else if(i % 2 == 1 && j % 2 == 1) a[i][j] = Inf;
				else cin >> a[i][j];
			}
		}
		a[0][0] = 1;
		if(a[0][1] == 0) qu.push(mypair(0, 2));
		if(a[1][0] == 0) qu.push(mypair(2, 0));
		bfs(qu.front().first, qu.front().second, 1);
		if(a[2*h-2][2*w-2] == Inf) cout << 0 <<endl;
		else cout << a[2*h-2][2*w-2] <<endl;
	}
	return 0;
}

void bfs(int y, int x, int step) {
	qu.pop();
	if(y < 0 || x < 0 || y >= 2*h-1 || x >= 2*w-1) return;
	if(step >= a[y][x]) return;
	else {
		step++;
		a[y][x] = step;
		if(x + 1 < 2*w-1) {
			if(a[y][x+1] == 0) {
				qu.push(mypair(y, x+2));
				bfs(qu.front().first, qu.front().second, step);
			}
		}
		if(y+1 < 2*h-1) { 
			if(a[y+1][x] == 0) {
				qu.push(mypair(y+2, x));
				bfs(qu.front().first, qu.front().second, step);
			}
		}
		if(y - 1 >= 0) {
			if(a[y-1][x] == 0) {
				qu.push(mypair(y-2, x));
				bfs(qu.front().first, qu.front().second, step);
			}
		}
		if(x - 1 >= 0) {
			if(a[y][x-1] == 0) {
				qu.push(mypair(y, x-2));
				bfs(qu.front().first, qu.front().second, step);
			}
		}
	}
	return;
}

C++: #include <iostream>
#include <queue>
#include <algorithm>
using namespace std;

struct P{
	int x, y;
	P(){}
	P(int x_, int y_){
		x = x_; y = y_;
	}
};

const int INF = 1e+8;
const int dx[4] = {0,0,-1,1};
const int dy[4] = {-1,1,0,0};
int c[100][100], d[100][100];

int bfs(int w, int h){
	queue<P> q;
	d[0][0] = 0;
	q.push( P(0, 0) );
	while( !q.empty() ){
		int x = q.front().x, y = q.front().y; q.pop();
		
		if( x == w - 1 && y == h - 1 ) return d[y][x] + 1;
		
		for(int i = 0 ; i < 4 ; i++ ){
			int mx = x + dx[i], my = y + dy[i];
			if( 0 <= mx && 0 <= my && mx < w && my < h && c[my][mx] == 0 ){
				int nx = mx + dx[i], ny = my + dy[i];
				if( 0 <= nx && 0 <= ny && nx < w && ny < h && d[ny][nx] == INF ){
					d[ny][nx] = d[y][x] + 1;
					q.push( P(nx, ny) );
				}
			}
		}
	}
	return 0;
}

int main(){
	int w, h;
	while( cin >> w >> h , w || h ){
		for(int y = 0 ; y < 100 ; y++ ){
			fill(c[y], c[y] + 100, 0);
			fill(d[y], d[y] + 100, INF);
		}
		
		for(int y = 0 ; y < 2 * h - 1 ; y++ ){
			if( y % 2 == 0 ){
				for(int x = 0 ; x < w - 1 ; x++ ){
					cin >> c[y][x * 2 + 1];
				}
			}else{
				for(int x = 0 ; x < w ; x++ ){
					cin >> c[y][x * 2];
				}
			}
		}
		int ans = bfs(w * 2 - 1, h * 2 - 1);
		cout << ans << endl;
	}
}