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 _USE_MATH_DEFINES
#include <algorithm>
#include <cstdio>
#include <functional>
#include <iostream>
#include <cfloat>
#include <climits>
#include <cstring>
#include <cmath>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <time.h>
#include <vector>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<ll, int> ll_i;
typedef pair<double, int> d_i;
typedef pair<ll, ll> ll_ll;
typedef pair<double, double> d_d;
struct edge { int u, v; ll w; };

ll MOD = 1000000007;
ll _MOD = 1000000009;
double EPS = 1e-10;

int main() {
	for (;;) {
		int w, h; cin >> w >> h;
		if (w == 0 && h == 0) break;
		vector< vector<int> > a(h, vector<int>(w - 1)), b(h - 1, vector<int>(w));
		for (int i = 0; i < h; i++) {
			for (int j = 0; j < w - 1; j++) cin >> a[i][j];
			if (i + 1 == h) continue;
			for (int j = 0; j < w; j++) cin >> b[i][j];
		}
		vector< vector<int> > d(h, vector<int>(w));
		d[0][0] = 1;
		queue<i_i> q;
		q.push(i_i(0, 0));
		while (!q.empty()) {
			i_i p = q.front(); q.pop();
			int i = p.first, j = p.second;
			if (i - 1 >= 0 && !b[i - 1][j] && !d[i - 1][j]) {
				d[i - 1][j] = d[i][j] + 1;
				q.push(i_i(i - 1, j));
			}
			if (i + 1 < h && !b[i][j] && !d[i + 1][j]) {
				d[i + 1][j] = d[i][j] + 1;
				q.push(i_i(i + 1, j));
			}
			if (j - 1 >= 0 && !a[i][j - 1] && !d[i][j - 1]) {
				d[i][j - 1] = d[i][j] + 1;
				q.push(i_i(i, j - 1));
			}
			if (j + 1 < w && !a[i][j] && !d[i][j + 1]) {
				d[i][j + 1] = d[i][j] + 1;
				q.push(i_i(i, j + 1));
			}
		}
		cout << d[h - 1][w - 1] << endl;
	}
}

C++: #include <cstdio>
#include <cstdlib>
#include <cmath>
#include <climits>
#include <cfloat>
#include <map>
#include <utility>
#include <set>
#include <iostream>
#include <memory>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
using namespace std;
static const double EPS = 1e-5;
typedef long long ll;
#define FOR(i,n) for(i=0;i<n;i++) 

int a[40][40];
int b[40][40];
int m[40][40];
int w,h;
int f(int x,int y,int d){
	if(m[x][y]<=d)return 0;
	m[x][y]=d;
	if(x>0&&!a[x-1][y])f(x-1,y,d+1);
	if(x<w-1&&!a[x][y])f(x+1,y,d+1);
	if(y>0&&!b[x][y-1])f(x,y-1,d+1);
	if(y<h-1&&!b[x][y])f(x,y+1,d+1);
	return 0;
}

int main(){
	for(;cin>>w>>h,w;){
		for(int i=0;i<40;i++)for(int j=0;j<40;j++){
			m[i][j]=INT_MAX/3;
		}
		for(int i=0;i<h-1;i++){
			for(int j=0;j<w-1;j++){
				cin>>a[j][i];
			}
			for(int j=0;j<w;j++){
				cin>>b[j][i];
			}
		}
		for(int i=0;i<w-1;i++){
			cin>>a[i][h-1];
		}
		f(0,0,1);
		if(m[w-1][h-1]!=INT_MAX/3){
			cout<<m[w-1][h-1]<<endl;
		}else{
			cout<<0<<endl;
		}
	}
	return 0;
}