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>
using namespace std;
#define all(vec) vec.begin(),vec.end()
typedef long long int ll;
typedef pair<ll,ll> P;
const ll MOD=10000;
const double INF=1000000000;
const int MAX=100001;
int dx[4]={0,1,0,-1};
int dy[4]={1,0,-1,0};
int c[40][40][40][40];
int main(){
    int w,h;
    while(cin>>w>>h,w+h){
        int ans[40][40]={};
        for(int i=0;i<2*h-1;i++){
            if(i%2){
                for(int j=0;j<w;j++){
                    cin>>c[i/2][j][i/2+1][j];
                }
            }else{
                for(int j=0;j<w-1;j++){
                    cin>>c[i/2][j][i/2][j+1];
                }
            }
        }
        queue<P> q;
        q.push(P(0,0));
        ans[0][0]=1;
        while(!q.empty()){
            int x=q.front().first;
            int y=q.front().second;
            q.pop();
            if(x==w-1&&y==h-1)break;
            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||c[y][x][ny][nx]||c[ny][nx][y][x]||ans[ny][nx]){
                    continue;
                }
                ans[ny][nx]=ans[y][x]+1;
                q.push(P(nx,ny));
            }
        }
        cout<<ans[h-1][w-1]<<endl;
    }
    return 0;
}

C++: #include <bits/stdc++.h>
 
using namespace std;
typedef long long ll;
 
#define rep(i, n) for(int i=0; i<(n); ++i)

typedef pair<int, int> P;

int wall_x[31][31];
int wall_y[31][31];
int d[31][31];
int main(void){
    int w, h;
    while(cin >> w >> h && w) {
        rep(i, 31) rep(j, 31) wall_x[i][j] = wall_y[i][j] = -1;
        rep(line, 2*h-1) {
            if(line%2==0) {
                rep(i, w-1) cin >> wall_x[line/2][i];
            } else {
                rep(i, w) cin >> wall_y[line/2][i];
            }
        }
        rep(i, 31) rep(j, 31) d[i][j] = 0;
        queue<P> que;
        que.push(P(0, 0));
        d[0][0] = 1;
        while(!que.empty()) {
            P p = que.front(); que.pop();
            int cy = p.first, cx = p.second;
            if(cy == h-1 && cx == w-1) break;

            if(cx>0 && wall_x[cy][cx-1]==0 && d[cy][cx-1]==0) {
                d[cy][cx-1] = d[cy][cx]+1;
                que.push(P(cy, cx-1));
            }
            if(cx<w-1 && wall_x[cy][cx]==0 && d[cy][cx+1]==0) {
                d[cy][cx+1] = d[cy][cx]+1;
                que.push(P(cy, cx+1));
            }
            if(cy>0 && wall_y[cy-1][cx]==0 && d[cy-1][cx]==0) {
                d[cy-1][cx] = d[cy][cx]+1;
                que.push(P(cy-1, cx));
            }
            if(cy<h-1 && wall_y[cy][cx]==0 && d[cy+1][cx]==0) {
                d[cy+1][cx] = d[cy][cx]+1;
                que.push(P(cy+1, cx));
            }
        }
        cout << d[h-1][w-1] << endl;
    }
}

C++: #include<bits/stdc++.h>
using namespace std;
#define INF 1000000
//aizu 200???

//??±???????????¢?´¢??§??????????????????
int h, w;
int di[4] = {0, 1, 0, -1};
int dj[4] = {1, 0, -1, 0};

void dfs(int si, int sj, int gi, int gj, int& ans, vector<vector<bool> >& canGo, int counter){

    if(counter + h + w - 2 >= ans) return;

    //??´???????????????ans?????´??°??????return
    if(si == gi && sj == gj){
        ans = min(ans, counter);
        return;
    }

    //???????????¨???????????¢?´¢?????????
    canGo[si][sj] = true;

    //??±???????????¢?´¢??????
    for(int k = 0; k < 4; k++){
        if(canGo[si + di[k]][sj + dj[k]] == 0){
            if(canGo[si + di[k]*2][sj + dj[k]*2] == 0){
                dfs(si + di[k]*2, sj + dj[k]*2, gi, gj, ans, canGo, counter + 1);
            }
        }
    }


    //???????????¨?????????????¨???????
    canGo[si][sj] = false;
    
}

int main(){
    cin >> w >> h;
    vector<vector<bool> > canGo(2*h + 2, vector<bool> (2*w + 2, true));
    for(int i = 1; i <= 2*h - 1; i++){
        for(int j = 1; j <= 2*w - 1; j++){
            canGo[i][j] = false;
        }
    }

    //??\???
    for(int i = 1; i <= 2*h - 1; i++){
        if(i % 2 == 1){
            for(int j = 2; j <= 2*w - 1; j += 2){
                bool input; cin >> input;
                canGo[i][j] = input;
            }
        }else{
            for(int j = 1; j <= 2*w - 1; j+= 2){
                bool input; cin >> input;
                canGo[i][j] = input;
            }
        }
    }

    //??????
    /*for(int i = 0; i < 2*h + 1; i++){
        for(int j = 0; j < 2*w + 1; j++){
            cout << canGo[i][j];
        }
        cout << endl;
    }*/

    int ans = INF;

    dfs(1, 1, 2*h-1, 2*w-1, ans, canGo, 0);

    if(ans != INF) cout << ans + 1 << endl;
    else cout << 0 << endl;
    return 0;

}