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 <string>
#include <vector>
#include <cmath>
#include <algorithm>
#include <cstdlib>
#include <ctime>
#include <cstdio>
#include <functional>
#include <set>
#include <sstream>
#include <map>
#include <queue>
#include <stack>

using namespace std;

int dx[]={0,1,0,-1};
int dy[]={-1,0,1,0};
typedef pair<int,int> p;

int main()
{
	int w,h;
	while(cin>>w>>h,w||h){
		
		//even;LR
		//odd:UD
		vector<vector<int> > even,odd;
		for(int i=0;i<2*h-1;i++){
			if(i%2==0){
				even.push_back(vector<int>(w-1));
				for(int j=0;j<w-1;j++){
					cin>>even[i/2][j];
				}
			}else{
				odd.push_back(vector<int>(w));
				for(int j=0;j<w;j++){
					cin>>odd[i/2][j];
				}
			}
		}
		
		int d[50][50];
		for(int i=0;i<50;i++){
			for(int j=0;j<50;j++){
				d[i][j]=1e7;
			}
		}
		d[0][0]=0;
		queue<p> q;
		
		q.push(p(0,0));
		while(!q.empty()){
			
			p pos=q.front();
			q.pop();
			int y=pos.first,x=pos.second;
			
			//cout<<"y="<<y<<" x="<<x<<" d="<<d[y][x]<<endl;
			
			//left
			int nx=x-1,ny=y;
			if( 0<=nx && nx<w && 0<=ny && ny<h && d[ny][nx]==1e7 && even[y][x-1]==0){
				d[ny][nx]=d[y][x]+1;
				q.push(p(ny,nx));
			}
			
			//right
			nx=x+1,ny=y;
			if( 0<=nx && nx<w && 0<=ny && ny<h && d[ny][nx]==1e7 && even[y][x]==0){
				d[ny][nx]=d[y][x]+1;
				q.push(p(ny,nx));
			}
			
			//up
			nx=x,ny=y-1;
			if( 0<=nx && nx<w && 0<=ny && ny<h && d[ny][nx]==1e7 && odd[y-1][x]==0){
				d[ny][nx]=d[y][x]+1;
				q.push(p(ny,nx));
			}
			
			nx=x,ny=y+1;
			if( 0<=nx && nx<w && 0<=ny && ny<h && d[ny][nx]==1e7 && odd[y][x]==0){
				d[ny][nx]=d[y][x]+1;
				q.push(p(ny,nx));
			}			
			
		}
		
		//cout<<h-1<<" "<<w-1<<endl;
		if(d[h-1][w-1]==1e7) d[h-1][w-1]=-1;
		cout<<d[h-1][w-1]+1<<endl;
		
	}
	
	
	return 0;
}

C++: #include "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
#define rep(i,n) for(ll i=0;i<(ll)(n);i++)
#define all(a)  (a).begin(),(a).end()
#define pb push_back
#define INF 99

int fie[40][40];
int w,h;
bool wall[33][33][4];
//map<pair<pii,pii>,bool> wall;

void bfs(int a,int b){
    bool used[40][40];
    rep(i,40)rep(j,40)used [i][j] = false;
    int dy[] = {-1,0,1,0};
    int dx[] = {0,1,0,-1};
    queue<pii> que;
    que.push(pii(a,b));
    while(que.size()){
        int y=que.front().first,x=que.front().second;
//        cout<<y<<" "<<x<<endl;
        if(y==h&&x==w)return ;
        used[y][x] = true;
        que.pop();
        rep(i,4){
            int ddy = y+dy[i],ddx = x+dx[i];
            if(ddy<0 || ddx<0 || ddy>h || ddx>w || used[ddy][ddx])continue;
//            cout<<i<<endl;
            if( wall[y][x][i]==1 )continue;
            fie[ddy][ddx] = min(fie[ddy][ddx],fie[y][x]+1);
            que.push(pii(ddy,ddx));
        }
    }
}


int main(){
    while(cin>>w>>h&&w&&h){
        rep(i,33)rep(j,33)rep(k,4)wall[i][j][k] = true;
        wall[0][1][2] = false;
        for(int i=1;i<=h;i++){
            for(int j=1;j<=w-1;j++){
                bool a;
                cin>>a;
                wall[i][j][1] = wall[i][j+1][3] = a;
            }
            if(i==h)continue;
            for(int j=1;j<=w;j++){
                bool a;
                cin>>a;
                wall[i][j][2] = wall[i+1][j][0] = a;
            }
        }
        rep(i,40)rep(j,40)fie[i][j] = INF;
        fie[0][1] = 0;
        bfs(0,1);
        if(fie[h][w] == INF)cout<<0<<endl;
        else cout<<fie[h][w]<<endl;
        
//        rep(i,h+1){
//            rep(j,w+1){
//                printf("%3d",fie[i][j]);
//            }
//            cout<<endl;
//        }
        
    }
}