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++: #define MYDEBUG
#include <iostream>
#include <fstream>
#include <vector>
#include <cstring>
#include <string>
#include <algorithm>
#include <math.h>
#include <queue>
#include <set>
#include <stack>

#ifdef MYDEBUG
#define debug(x) cout<<#x<<": "<<x<<endl 
#else
#define debug(x)
#endif
#define ll long long
#define ull unsigned long long
#define eps 1e-14
#define all(x) x.begin(), x.end()
using namespace std;

template<typename T>
ostream& operator<<(ostream& out, const vector<T>& v) {
  out << "[";
  size_t last = v.size() - 1;
  for (size_t i = 0; i < v.size(); ++i) {
    out << v[i];
    if (i != last)
      out << ",";
  }
  out << "]";
  return out;
}

int W,H;
const int MAXW = 30*2+1;
int cnt[MAXW][MAXW];
int ng[MAXW][MAXW];
int di[4] = {-2,0,2,0};
int dj[4] = {0,2,0,-2};
int W2,H2;

void bfs(int si, int sj, int gi, int gj){
	queue<int> qi;
	queue<int> qj;
	qi.push(si);
	qj.push(sj);
	while(!qi.empty()){
		int i = qi.front(), j = qj.front();
		qi.pop(); qj.pop();
		if(i==gi&&j==gj) return;
		for(int k=0; k<4; ++k){
			int ni=i+di[k], nj=j+dj[k];
			if(0<=ni&&ni<H2&&0<=nj&&nj<W2&&//???????????????????????????
			cnt[ni][nj]==0&&//????¨????(=0)????????¢?´¢
			ng[i+di[k]/2][j+dj[k]/2]==0){//???????£?????????????(i??¨i+2?????????i+2/2)
				qi.push(ni);
				qj.push(nj);
				cnt[ni][nj]=cnt[i][j]+1;
			}
		}
	}
}

void solve(){
	//ifstream cin("/storage/emulated/0/AppProjects/AtCoder/jni/in.txt");
	while(true){
		cin >> W >> H;
		if(W==0&&H==0) return;
		W2=2*W-1;
		H2=2*H-1;
		for(int i=0; i<MAXW; ++i){
			for(int j=0; j<MAXW; ++j){
				ng[i][j]=0;
				cnt[i][j]=0;
			}
		}
		for(int i=0; i<H; ++i){
			for(int j=0; j<W-1; j++){//v
				cin >> ng[i*2][j*2+1];
			}
			if(i==H-1) break;
			for(int j=0; j<W; j++){//h
				cin >> ng[i*2+1][j*2];
			}
		}
		bfs(0,0,H2-1, W2-1);
		int ans = cnt[H2-1][W2-1];
		if(ans>0) ans++;
		cout << ans << endl;
	}
}

int main() {
	solve();
}

C++: # define _CRT_SECURE_NO_WARNINGS 1
# include <iostream>
# include <numeric>
# include <string>
# include <bitset>
# include <vector>
# include <algorithm>
# include <cstdlib>
# include <cstdio>
# include <cstring>
# include <cstdlib>
# include <iomanip>
# include <queue>
# include <sstream>
# include <climits>
# include <cmath>
# include <list>
# include <functional>
# include <string>
# include <ctime>
# include <set>
# include <map>
# include <stack>
using namespace std;
//# define M_PI 3.141592
# define INF ((int)(1<<30))
# define FOR(i,n) for(int i=0;i<(int)n;i++)
# define FORI(i,k,n) for(int i=k;i<(int)n;i++)
# define toRad 2.0*M_PI/360.0
# define inin(x) int x;cin>>x;
# define all(x) x.begin(),x.end()
# define debug(x) cout<<#x<<" :"<<x<<endl;
# define rep(i,n) for(int i=0;i<(int)n;i++)
# define EPS 1e-12
# define CHECK(i,a) FOR(i,a.size())cout<<#a<<"["<<i<<"] : "<<a[i]<<endl; 
typedef vector<int> vi;
typedef vector<string> vs;
typedef pair<int, int> pii;
typedef pair<int, pii> piii;
int dx[4] = { 0,-1,1,0 }, dy[4] = { 1,0,0,-1 };

int main()
{
	int x, y;
	while (cin >> x >> y&&x)
	{
		int r[40][40] = {};
		int d[40][40] = {};
		for (int i = 1; i <= y; i++)
		{
			{
				for (int j = 1; j < x; j++)
				{
					inin(k);
					if (k == 0)
					{
						r[i][j] = 1;
					}
				}
			}
			{
				if (i == y)continue;
				for (int j = 1; j <= x; j++)
				{
					inin(k);
					if (k == 0)
					{
						d[i][j] = 1;
					}
				}
			}
		}
		int flag[40][40];
		FOR(i, 40)FOR(j, 40)flag[i][j] = INT_MAX;
		priority_queue<piii, vector<piii>, greater<piii> > que;
		piii start = piii(1, pii(1, 1));
		que.push(start);
		flag[1][1] = 1;
		int DX[4] = { 0,-1,0,0 }, DY[4] = { 0,0,0,-1 };
		bool ok = false;
		while (!que.empty())
		{
			piii now = que.top(); que.pop();
			if (now.second.first == x&&now.second.second == y)
			{
				cout << now.first << endl;
				ok = true;
				break;
			}
			for (int i = 0; i < 4; i++)
			{
				int X = now.second.first + dx[i];
				int Y = now.second.second + dy[i];
				int XX = now.second.first + DX[i];
				int YY = now.second.second + DY[i];
				//if (XX < 0 || YY < 0)continue;
				if (i == 0 || i == 3)
				{
					if (d[YY][XX] == 0)continue;
				}
				else
				{
					if (r[YY][XX] == 0)continue;
				}
				if (flag[Y][X] <= now.first + 1)continue;
				piii next;
				next.first = now.first + 1;
				next.second.first = X;
				next.second.second = Y;
				flag[Y][X] = now.first + 1;
				que.push(next);
			}
		}
		if (!ok)
		{
			cout << 0 << endl;
		}

	}
}