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 <vector>
#include <string>
#include <algorithm>
#include <cstring>
#include <map>
#include <queue>
#include <stack>
#include <set>
#include <functional>
#include <sstream>
#include <complex>
#include <climits>
using namespace std;

#define REP(i,a,n) for(int i=(a);i<(int)(n);i++)
#define rep(i,n) REP(i,0,n)
#define pb push_back
#define mp make_pair
#define all(x) x.begin(),x.end()
#define EPS 1e-8

class cell{
public:
	int dir[4]; // up,right,down,left;
};

int main(){
	cell field[32][32];
	const int dx[] = { 0, 1, 0,-1};
	const int dy[] = {-1, 0, 1, 0};
	int check[32][32];
	int w,h,s;
	while(scanf("%d%d",&w,&h),w|h){
		rep(i,32)rep(j,32)check[i][j]=INT_MAX;
		rep(i,2*h-1){
			if( i%2==0 ){	 // tatesen
				rep(j,w-1){
					scanf("%d",&s);
					field[i/2][j].dir[1] = field[i/2][j+1].dir[3] = s;
				}
			}else{ // yokosen
				rep(j,w){
					scanf("%d",&s);
					field[i/2][j].dir[2] = field[i/2+1][j].dir[0] = s;
				}
			}
		}
		/*
		rep(i,h){
			rep(j,w){
				printf("(%d,%d) u:%d, r:%d, d:%d, l:%d\n",j,i,field[i][j].dir[0],field[i][j].dir[1],field[i][j].dir[2],field[i][j].dir[3]);
			}
		}
		*/
		
		
		queue<pair<int,int> > q;
		q.push(mp(0,0));
		check[0][0] = 0;
		bool goal = false;
		while(!q.empty()){
			int x = q.front().first;
			int y = q.front().second;
			int c = check[y][x];
			q.pop();
			rep(k,4){
				int tx = x + dx[k];
				int ty = y + dy[k];
				//printf("(%d,%d) c:%d\n",tx,ty,c);
				if( tx<0 || ty<0 || tx>=w || ty>=h || check[ty][tx]<=c+1 ) continue;
				if( field[y][x].dir[k]==1 ) continue;
				//printf("(%d,%d):%d --> dir:%d --> (%d,%d):%d\n",x,y,c,k,tx,ty,check[ty][tx]);
				check[ty][tx] = c+1;
				if( tx==w-1 && ty==h-1 ){
					goal = true; break;
				}
				q.push(mp(tx,ty));
			}
			if( goal ) break;
			//printf("size:%d\n",q.size());
		}
		printf("%d\n",check[h-1][w-1]==INT_MAX?0:check[h-1][w-1]+1);
	}
	return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define all(v) v.begin(),v.end()
#define _GLIBCXX_DEBUG
#define fi first
#define se second

using ll = long long;
using vi = vector<int>;
using vll = vector<ll>;
using vd = vector<double>;
using vvi = vector<vi>;
using vvll = vector<vll>;
using vvd = vector<vd>;
using vvvi = vector<vvi>;
using vvvll = vector<vvll>;
using vvvd = vector<vvd>;

const double pi=acos(-1);
const ll MOD=1e9+7;
const ll INF=(1LL<<60);

int main() {
    while (1){
        int h,w;
        cin>>w>>h;
        if (h==0)return 0;
        int g[h][w][h][w];
        memset(g,0,sizeof(g));
        rep(i,2*h-1){
            if (i%2==0){
                rep(j,w-1){
                    int b;
                    cin>>b;
                    if(b==0){
                        g[i/2][j][i/2][j+1]=1;
                        g[i/2][j+1][i/2][j]=1;
                    }
                }
            }
            else{
                rep(j,w){
                    int b;
                    cin>>b;
                    if (b==0){
                        g[i/2][j][i/2+1][j]=1;
                        g[i/2+1][j][i/2][j]=1;
                    }
                }
            }
        }
        queue<pair<int,int>> q;
        vvi d(h,vi(w,1000));
        d[0][0]=0;
        q.push({0,0});
        vector<pair<int,int>> move;
        move.push_back(make_pair(1,0));
        move.push_back(make_pair(-1,0));
        move.push_back(make_pair(0,1));
        move.push_back(make_pair(0,-1));
        while(q.size()!=0){
            auto p=q.front();
            q.pop();
            int x1=p.fi,y1=p.se;
            for (auto p1:move){
                int x=x1+p1.fi,y=y1+p1.se;
                if (x<0||y<0||x>=h||y>=w)continue;
                else if (g[x1][y1][x][y]==0)continue;
                else if (d[x][y]<=d[x1][y1]+1)continue;
                else{
                    d[x][y]=d[x1][y1]+1;
                    q.push({x,y});
                }
            }
        }
        if (d[h-1][w-1]==1000)cout<<0<<endl;
        else cout<<d[h-1][w-1]+1<<endl;
    }

    return 0;
}