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 <algorithm>
# include <vector>
# include <string>
# include <set>
# include <map>
# include <cmath>
# include <iomanip>
# include <functional>
# include <utility>
# include <stack>
# include <queue>
# include <list>
# include <tuple>
# include <unordered_map>
# include <numeric>
# include <complex>
# include <bitset>
# include <random>
# include <chrono>
# include <cstdlib>
# include <tuple>
using namespace std;
using LL = long long;
using ULL = unsigned long long;
constexpr int INF = 2147483647;
constexpr int HINF = INF / 2;
constexpr double DINF = 100000000000000000.0;
constexpr double HDINF = 50000000000000000.0;
constexpr long long LINF = 9223372036854775807;
constexpr long long HLINF = 4500000000000000000;
const double PI = acos(-1);
template <typename T_char>T_char TL(T_char cX) { return tolower(cX); };
template <typename T_char>T_char TU(T_char cX) { return toupper(cX); };
const int vy[] = { -1, -1, -1, 0, 1, 1, 1, 0 }, vx[] = { -1, 0, 1, 1, 1, 0, -1, -1 };
const int dx[4] = { 0,1,0,-1 }, dy[4] = { 1,0,-1,0 };
# define ALL(x)      (x).begin(),(x).end()
# define UNIQ(c)     (isok).erase(unique(ALL((isok))),(isok).end())
# define LOWER(s)    transform(ALL((maze)),(maze).begin(),TL<char>)
# define UPPER(s)    transform(ALL((maze)),(maze).begin(),TU<char>)
# define FOR(i,a,b)  for(LL i=(a);i<(b);i++)
# define RFOR(i,a,b) for(LL i=(a);i>=(b);i--)
# define REP(i,n)    FOR(i,0,n)
# define INIT        std::ios::sync_with_stdio(false);std::cin.tie(0)


bool iswall[70][70][70][70];
int h, w;
int sx, sy, gx, gy;

int d[70][70];
int bfs() {
	queue<pair<int, int>> que;
	for (int i = 0; i < h; i++) {
		for (int j = 0; j < w; j++) {
			d[i][j] = HINF;
		}
	}
	que.push(pair<int, int>(sx, sy));
	d[sy][sx] = 0;
	while (que.size()) {
		pair<int, int> p = que.front();
		que.pop();
		for (int i = 0; i < 4; i++) {
			int nx = p.first + dx[i], ny = p.second + dy[i];
			if (iswall[p.second][p.first][ny][nx] == 1)continue;
			if (0 <= nx&&nx < w && 0 <= ny&&ny < h && d[ny][nx] == HINF) {
				que.push(pair<int, int>(nx, ny));
				d[ny][nx] = d[p.second][p.first] + 1;
				//cout << p.second << " " << p.first << endl;
				//cout <<" "<< ny << " " << nx << endl;
				//system("pause");
			}
		}
	}
	return d[gy][gx];
}

int num;
int main() {
	while (cin >> w >> h&&w&&h) {
		REP(i, 70)REP(j, 70)d[i][j] = 0;
		REP(i, 70)REP(j, 70)REP(k, 70)REP(l, 70)iswall[i][j][k][l] = 0;

		REP(i, 2 * h - 1) {
			if (i % 2 == 0) {
				REP(j, w - 1) {
					cin >> num;
					iswall[i/2][j][i/2][j + 1] = iswall[i/2][j + 1][i/2][j] = num;
				}
			}
			else {
				REP(j, w) {
					cin >> num;
					iswall[(i) / 2][j][(i) / 2 + 1][j] = iswall[(i) / 2 + 1][j][(i)/2][j] = num;
				}
			}
		}
		sy = 0, sx = 0;
		gy = h - 1, gx = w - 1;
		LL ret = bfs();
		cout << (ret == HINF ? 0 : ret + 1) << endl;
	}
}

C++: #include<cstdio>
#include<algorithm>
#define	MM 2000000000
using namespace std;

int main(void)
{
	int w,h,i,j,k,ii,jj,a[31][31],x,y,xx,yy,flg;
	int ue[31][31],yoko[31][31];
	while(1)	{
		scanf("%d %d",&w,&h);
		if(w==0 && h==0)	break;
		for(i=0;i<h;i++)	{
			for(j=0;j<w-1;j++)	{
				scanf("%d",&yoko[i][j]);
			}
			if(i!=h-1)	{
				for(j=0;j<w;j++)	{
					scanf("%d",&ue[i][j]);
				}
			}
		}
		for(i=0;i<h;i++)	{
			for(j=0;j<w;j++)	{
				a[i][j]=MM;
			}
		}
		a[0][0]=1;
		for(i=1;i<=w*h;i++)	{
			flg=0;
			for(j=0;j<h;j++)	{
				for(k=0;k<w;k++)	{
					if(a[j][k]==i)	{
						flg=1;
						if(j>0 && ue[j-1][k]==0 && a[j-1][k]==MM)	{
							a[j-1][k]=i+1;
						}
						if(j<h-1 && ue[j][k]==0 && a[j+1][k]==MM)	{
							a[j+1][k]=i+1;
						}
						if(k>0 && yoko[j][k-1]==0 && a[j][k-1]==MM)	{
							a[j][k-1]=i+1;
						}
						if(k<w-1 && yoko[j][k]==0 && a[j][k+1]==MM)	{
							a[j][k+1]=i+1;
						}
					}
				}
			}
			if(flg==0)	break;
			if(a[h-1][w-1]==i+1)	break;
		}
		if(flg==0)	printf("0\n");
		else 	printf("%d\n",i+1);
	}
	return 0;
}