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 "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[aa]; if (aa != 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); }
///(テつエテ」ツδサテ渉嘉」ツδサ`)(テつエテ」ツδサテ渉嘉」ツδサ`)(テつエテ」ツδサテ渉嘉」ツδサ`)(テつエテ」ツδサテ渉嘉」ツδサ`)(テつエテ」ツδサテ渉嘉」ツδサ`)(テつエテ」ツδサテ渉嘉」ツδサ`)///

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

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

C++: #include<bits/stdc++.h>
#define fi first
#define se second
#define inf 999999999
using namespace std;
int h,w;
bool c[40][40],d[40][40];
int dx[]={-1,0,0,1};
int dy[]={0,1,-1,0};
inline int bfs(){
    int res=inf;
    bool past[40][40];
    for(int i=0;i<40;i++)for(int j=0;j<40;j++)past[i][j]=0;
    queue<pair<int,pair<int,int> > > q;
    q.push(pair<int,pair<int,int> >(0,pair<int,int>(0,0)));
    while(!q.empty()){
        int nowy=q.front().fi;
        int nowx=q.front().se.fi;
        int nowcost=q.front().se.se;
        q.pop();
       // cout<<"nowy="<<nowy<<"nowx="<<nowx<<"nowcost="<<nowcost<<endl;
        if(nowx==w-1 && nowy==h-1){
            res=min(nowcost,res);
            continue;
        }
       // cout<<"hi"<<endl;
        if(past[nowy][nowx]==1)continue;
        else past[nowy][nowx]=1;
       // cout<<"hi"<<endl;
        for(int i=0;i<4;i++){
            if(nowx+dx[i]>=0 && nowx+dx[i]<w && nowy+dy[i]>=0 && nowy+dy[i]<h){
                if(i==0 && c[nowy][nowx-1]==0){
                   // cout<<"hi0"<<endl;
                    q.push(pair<int,pair<int,int> >(nowy,pair<int,int>(nowx-1,nowcost+1)));
                }
                if(i==1 && d[nowy][nowx]==0){
                   // cout<<"hi1"<<endl;
                    q.push(pair<int,pair<int,int> >(nowy+1,pair<int,int>(nowx,nowcost+1)));
                }
                if(i==2 && d[nowy-1][nowx]==0){
                  // cout<<"hi2"<<endl;
                   q.push(pair<int,pair<int,int> >(nowy-1,pair<int,int>(nowx,nowcost+1)));
                 }
                if(c[nowy][nowx]==0 && i==3){
                   // cout<<"hi3"<<endl;
                    q.push(pair<int,pair<int,int> >(nowy,pair<int,int>(nowx+1,nowcost+1)));
                }
            }
        }
    }
    return res;
}
int main(){
    while(cin>>w>>h,w){
        for(int i=0;i<40;i++)for(int j=0;j<40;j++)c[i][j]=0,d[i][j]=0;
        int a=w-1;
        int b=w;
        for(int i=0;i<h;i++){
            for(int j=0;j<a;j++){
                cin>>c[i][j];
            }
            if(i!=h-1)for(int j=0;j<b;j++){
                cin>>d[i][j];
            }else continue;
        }
        if(bfs()==inf){
            cout<<0<<endl;
        }else{
            cout<<bfs()+1<<endl;
        }
    }
}