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 <iomanip>
#include <vector>
#include <set>
#include <string>
#include <queue>
#include <algorithm>
#include <map>
#include <cmath>
#include <numeric>
#include <list>
#include <stack>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <tuple>

#define rep(i, n) for (int i = 0; i < (n); i++)
#define rep1(i, n) for (int i = 1; i <= (n); i++)
#define show(a, n) rep(i,n) {cout<<a[i]<<' ';} cout<<endl;

using namespace std;
typedef vector<int> vi;
typedef pair<int, int> pii;
typedef long long ll;
typedef vector<ll> vll;
typedef pair<long long, long long> pll;

const int INF = 1 << 30;
const long long INFL = 1LL << 62;
const int MOD = 1000000007;
const int MAX = 100000;
const int N = 100010;

int bfs(vector<vi>& wx, vector<vi>& wy) {
	int h = wx.size();
	int w = wx[0].size() + 1;
	vector<vi> d(h, vi(w, 0));
	queue<pii> que;
	que.push(pii(0, 0));
	d[0][0] = 1;
	while(!que.empty()) {
		pii p = que.front();
		que.pop();
		int i = p.first, j = p.second;
		if(i < h-1 && wy[i][j] == 0 && d[i+1][j] == 0) {
			d[i+1][j] = d[i][j] + 1;
			que.push(pii(i+1, j));
		}
		if(i > 0 && wy[i-1][j] == 0 && d[i-1][j] == 0) {
			d[i-1][j] = d[i][j] + 1;
			que.push(pii(i-1, j));
		}
		if(j < w-1 && wx[i][j] == 0 && d[i][j+1] == 0) {
			d[i][j+1] = d[i][j] + 1;
			que.push(pii(i, j+1));
		}
		if(j > 0 && wx[i][j-1] == 0 && d[i][j-1] == 0) {
			d[i][j-1] = d[i][j] + 1;
			que.push(pii(i, j-1));
		}
	}
	return d[h-1][w-1];
}

int main() {
//	cout << fixed << setprecision(15);
	vi ans;
	while(true) {
		int w, h;
		cin >> w >> h;
		if(w == 0 && h == 0) break;
		vector<vi> wx(h, vi(w-1)), wy(h-1, vi(w));
		rep(i, 2*h - 1) {
			if(i % 2 == 0) rep(j, w-1) cin >> wx[i/2][j];
			else rep(j, w) cin >> wy[i/2][j];
		}
		ans.push_back(bfs(wx, wy));
	}
	for(auto i : ans) cout << i << endl;
}

C++: #include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <fstream>
#include <queue>

#pragma warning( disable: 4996 )

using namespace std;

typedef long long ll;
typedef pair<int, int> P;

#define INF 100000000
#define EPS 1e-9

#define MAX_W 30
#define MAX_H 30

int W, H;

vector<int> ans_list;

int dp[MAX_H][MAX_W];
int maze[MAX_H][MAX_W];

int dx[] = { 1, 0, -1, 0 };
int dy[] = { 0, -1, 0, 1 };

void solve(){

	queue<P> que;

	que.push(P(0, 0));

	while (que.size()){
		
		P p = que.front();
		int x = p.first;
		int y = p.second;
		que.pop();

		for (int i = 0; i < 4; i++){
			int nx = x + dx[i];
			int ny = y + dy[i];
			if (nx >= 0 && nx < W && ny >= 0 && ny < H && dp[ny][nx] == INF && (maze[y][x] >> i) & 1){
				dp[ny][nx] = dp[y][x] + 1;
				que.push(P(nx, ny));
			}
		}

	}


}

int main(){

	while (true){
	
		cin >> W >> H;
		if (W == 0 && H == 0)
			break;

		for (int i = 0; i < H; i++){
			for (int j = 0; j < W; j++){
				maze[i][j] = 15;
				dp[i][j] = INF;
			}
		}

		dp[0][0] = 1;

		int num[MAX_W];

		for (int i = 0; i < 2 * H - 1; i++){
			//横方向
			if (i % 2 == 0){
				for (int j = 0; j < W - 1; j++){
					cin >> num[j];
					if (num[j] == 1){
						maze[i / 2][j] -= 1;
						maze[i / 2][j + 1] -= 4;
					}
				}
			}

			//縦方向
			if (i % 2 != 0){
				for (int j = 0; j < W; j++){
					cin >> num[j];
					if (num[j] == 1){
						maze[i / 2][j] -= 8;
						maze[(i + 1) / 2][j] -= 2;
					}
				}
			}

		}

		solve();
		int ans = dp[H - 1][W - 1];
		if (ans != INF)
			ans_list.push_back(ans);
		else
			ans_list.push_back(0);
	
	}

	for (int i = 0; i < ans_list.size(); i++){
		cout << ans_list[i] << endl;
	}

	return 0;

}