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 <cstdio>
#include <queue>

#define rep(i,n) for(int i=0;i<(n);i++)
#define fr first
#define sc second
int dy[]={1,0,-1,0};
int dx[]={0,1,0,-1};

using namespace std;
typedef pair<int,int> P;
int W,H;
string maze[100];
const int INF=1e9;

void solve() {
    int dp[100][100];
    rep(y,100) rep(x,100) dp[y][x]=INF;
    getchar();
    rep(y,2*H-1) getline(cin,maze[y]);

    queue<P> que;
    que.push(P(0,0));
    dp[0][0]=0;
    while(que.size()) {
        P p=que.front(); que.pop();
        rep(k,4) {
            int ny=p.fr+dy[k];
            int nx=p.sc+dx[k];
            int ny2=ny+dy[k];
            int nx2=nx+dx[k];
            if(!(0<=ny&&ny<2*H-1)) continue;
            if(!(0<=nx&&nx<2*W-1)) continue;
            if(!(0<=ny2&&ny2<2*H-1)) continue;
            if(!(0<=nx2&&nx2<2*W-1)) continue;
            if(dp[ny2][nx2]!=INF) continue;
            if(maze[ny][nx]=='1') continue;

            //printf("(%d, %d) -> (%d, %d)\n",p.fr,p.sc,ny2,nx2);
            dp[ny2][nx2]=dp[p.fr][p.sc]+1;
            que.push(P(ny2,nx2));
        }
    }

    int ans=dp[2*H-2][2*W-2];
    if(ans==INF) ans=0;
    else ans++;
    cout<<ans<<endl;
}

int main() {
    while(cin>>W>>H) {
        if(!W) break;
        solve();
    }
    return 0;
}

C++: #include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <map>
#include <set>
#include <list>
#include <queue>
#include <deque>
#include <stack>
#include <vector>
#include <algorithm>
#include <functional>
#include <cstring>
#include <string>
#include <sstream>
#include <bitset>
using namespace std;
#define INF	100000000
#define MOD 1000000007
#define pb push_back
#define mp make_pair
#define fi first
#define sec second
#define lb lower_bound
#define ub upper_bound
#define SS stringstream
#define rep(i,n) for(int i = 0; i < n; i++)
#define SORT(x) sort((x).begin(), (x).end())
#define clr(a,b) memset((a),(b),sizeof(a))
typedef long long int ll;
typedef pair<int, int> P;
typedef vector<int> Vi;
typedef vector<ll> Vll;
typedef vector<P> Vp;
typedef priority_queue<P, vector<P>, greater<P> > PQ;

int dh[4] = {1,0,-1,0}, dw[4] = {0,1,0,-1};

int main(){
	int w,h;
	while(scanf("%d%d",&w,&h),w||h){
		int yoko[110][110],tate[110][110], cnt[110][110];
		rep(i,110) rep(j,110) cnt[i][j] = INF;
		cnt[0][0] = 1;
		rep(i,2*h-1){
			if(i%2==0){
				rep(j,w-1) scanf("%d", &tate[i/2][j]);
			} else{
				rep(j,w) scanf("%d", &yoko[i/2][j]);
			}
		}
		queue<P> que;
		que.push(P(0,0));
		while(true){
			if(que.size() == 0){
				printf("0\n");
				break;
			}
			P p = que.front(); que.pop();
			if(p.fi == h-1 && p.sec == w-1){
				printf("%d\n", cnt[h-1][w-1]);
				break;
			}
			//cout << p.fi << " " << p.sec << endl;
			if(p.fi != 0){
				if(yoko[p.fi-1][p.sec] == 0 && cnt[p.fi-1][p.sec] > cnt[p.fi][p.sec]+1){
					que.push(P(p.fi-1,p.sec));
					cnt[p.fi-1][p.sec] = cnt[p.fi][p.sec]+1;
				}
			}
			if(p.fi != h-1){
				if(yoko[p.fi][p.sec] == 0 && cnt[p.fi+1][p.sec] > cnt[p.fi][p.sec]+1){
					que.push(P(p.fi+1,p.sec));
					cnt[p.fi+1][p.sec] = cnt[p.fi][p.sec]+1;
				}
			}
			if(p.sec != 0){
				if(tate[p.fi][p.sec-1] == 0 && cnt[p.fi][p.sec-1] > cnt[p.fi][p.sec]+1){
					que.push(P(p.fi,p.sec-1));
					cnt[p.fi][p.sec-1] = cnt[p.fi][p.sec]+1;
				}
			}
			if(p.sec != w-1){
				if(tate[p.fi][p.sec] == 0 && cnt[p.fi][p.sec+1] > cnt[p.fi][p.sec]+1){
					que.push(P(p.fi,p.sec+1));
					cnt[p.fi][p.sec+1] = cnt[p.fi][p.sec]+1;
				}
			}
		}
	}
}