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 <queue>
using namespace std;

#define INF (1<<30)
#define MP make_pair

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

class State
{
public:
	int x,y,c;
	State(int x, int y, int c)
	:x(x),y(y),c(c)
	{}
};

int main()
{
	int W,H,t;
	while(cin >> W >> H, W||H)
	{
		int nodeX[32][32][32]={0};
		int nodeY[32][32][32]={0};		

		for(int y=0; y<H; y++)
		{
			for(int x=0; x<W-1; x++)
			{
				cin >> t;
				nodeX[x][x+1][y] = t;
				nodeX[x+1][x][y] = t;
			}
			
			if(y!=H-1)
			for(int x=0; x<W; x++)
			{
				cin >> t;
				nodeY[x][y][y+1] = t;
				nodeY[x][y+1][y] = t;
			}
		}

		queue<State> q;
		
		q.push(State(0,0,1));
		
		bool h[35][35]={0};
		
		bool g=false;
		while(!q.empty())
		{
			State s=q.front(); q.pop();
			if(s.x == W-1 && s.y == H-1)
			{
				g=true;
				cout << s.c << endl;
				break;
			}
			
			for(int i=0; i<2; i++)
			{
				int tx=s.x+dx[i], ty=s.y+dy[i];
				if(tx<0||ty<0||tx>=W||ty>=H) continue;
				if(nodeX[s.x][tx][ty]==1) continue;
				
				
				if(h[tx][ty]) continue;
				h[tx][ty]=1;
				
				q.push(State(tx,ty,s.c+1));
				
				
			}
			for(int i=2; i<4; i++)
			{
				int tx=s.x+dx[i], ty=s.y+dy[i];
				if(tx<0||ty<0||tx>=W||ty>=H) continue;
				
				if(nodeY[tx][s.y][ty]==1) continue;
				
				if(h[tx][ty]) continue;
				h[tx][ty]=1;
				
				q.push(State(tx,ty,s.c+1));
			}
			
		}
		
		if(!g) cout << 0 << endl;
		
	
	}

}

C++: #include "bits/stdc++.h"

#define REP(i,n) for(ll i=0;i<n;++i)
#define RREP(i,n) for(ll i=n-1;i>=0;--i)
#define FOR(i,m,n) for(ll i=m;i<n;++i)
#define RFOR(i,m,n) for(ll i=n-1;i>=m;--i)
#define ALL(v) (v).begin(),(v).end()
#define PB(a) push_back(a)
#define UNIQUE(v) v.erase(unique(ALL(v)),v.end());
#define DUMP(v) REP(aa, (v).size()) { cout << v[a]; if (a != v.size() - 1)cout << " "; else cout << endl; }
#define INF 1000000001ll
#define MOD 1000000007ll
#define EPS 1e-9

const int dx[8] = { 1,1,0,-1,-1,-1,0,1 };
const int dy[8] = { 0,1,1,1,0,-1,-1,-1 };


using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
ll max(ll a, int b) { return max(a, ll(b)); }
ll max(int a, ll b) { return max(ll(a), b); }
ll min(ll a, int b) { return min(a, ll(b)); }
ll min(int a, ll b) { return min(ll(a), b); }
///(?´????????`)(?´????????`)(?´????????`)(?´????????`)(?´????????`)(?´????????`)///

int h, w;
int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	while (1) {
		cin >> w >> h;
		if (!w)break;
		vector<vector<vvi>> v(w, vector<vvi>(h, vvi(w, vi(h, INF))));
		REP(i, 2 * h - 1) {
			if (i % 2 == 0) {
				REP(j, w - 1) {
					cin >> v[j][i / 2][j + 1][i / 2];
					v[j + 1][i / 2][j][i / 2] = v[j][i / 2][j + 1][i / 2];
				}
			}
			else {
				REP(j, w) {
					cin >> v[j][(i - 1) / 2][j][(i + 1) / 2];
					v[j][(i + 1) / 2][j][(i - 1) / 2] = v[j][(i - 1) / 2][j][(i + 1) / 2];
				}
			}
		}
		queue<pii> q;
		q.push({ 0,0 });
		vvi level(w, vi(h, INF));
		level[0][0] = 0;
		while (!q.empty()) {
			auto c = q.front(); q.pop();
			int cx = c.first, cy = c.second;
			REP(i, 4) {
				int nx = cx + dx[i * 2], ny = cy + dy[2 * i];
				if (nx < w&&ny < h&&nx >= 0 && ny >= 0 && v[cx][cy][nx][ny] == 0 && level[nx][ny]>level[cx][cy]) {
					q.push({ nx,ny });
					level[nx][ny] = level[cx][cy] + 1;
				}
			}
		}

		if (level[w - 1][h - 1] == INF)cout << 0 << endl;
		else cout << level[w - 1][h - 1] + 1 << endl;
	}
	return 0;
}