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<stdio.h>
#include<iostream>
#include<math.h>
#include<algorithm>
#include<string>
#include<utility>
#include<queue>
#define pi 3.14159
#define Inf (int)pow(2., 20.)

using namespace std;
typedef std::pair<int, int> mypair;
int w, h, a[59][59];
queue<mypair> qu;
void bfs(int y, int x);

int main(){
	while(1) {
		cin >> w >> h;
		if(w == 0 && h == 0) break;
		for(int i = 0; i < 2*h-1; i++) {
			for(int j = 0; j < 2*w-1; j++) {
				if(i % 2 == 0 && j % 2 == 0) a[i][j] = Inf;
				else if(i % 2 == 1 && j % 2 == 1) a[i][j] = Inf;
				else cin >> a[i][j];
			}
		}
		a[0][0] = 1;
		if(a[0][1] == 0) {
			qu.push(mypair(0, 2));
			a[0][2] = 2;
		}
		if(a[1][0] == 0) {
			qu.push(mypair(2, 0));
			a[2][0] = 2;
		}
		bfs(qu.front().first, qu.front().second);
		if(a[2*h-2][2*w-2] == Inf) cout << 0 <<endl;
		else cout << a[2*h-2][2*w-2] <<endl;
		
	}
	return 0;
}

void bfs(int y, int x) {
	qu.pop();
	
	if(y == 2*h-2 && x == 2*w-2) return;
	if(x + 1 < 2*w-1) {
		if(a[y][x+1] == 0 && a[y][x+2] > a[y][x] + 1) {
			qu.push(mypair(y, x+2));
			a[y][x+2] = a[y][x] + 1;
		}
	}
	if(y+1 < 2*h-1) { 
		if(a[y+1][x] == 0 && a[y+2][x] > a[y][x] + 1) {
			qu.push(mypair(y+2, x));
			a[y+2][x] = a[y][x] + 1;
		}
	}
	if(y - 1 >= 0) {
		if(a[y-1][x] == 0 && a[y-2][x] > a[y][x] + 1) {
			qu.push(mypair(y-2, x));
			a[y-2][x] = a[y][x] +1;
		}
	}
	if(x - 1 >= 0) {
		if(a[y][x-1] == 0 && a[y][x-2] > a[y][x] + 1) {
			qu.push(mypair(y, x-2));
			a[y][x-2] = a[y][x] + 1;
		}
	}
	if(qu.empty() == false) bfs(qu.front().first, qu.front().second);
	return;
}

C++: #include "bits/stdc++.h"

#define REP(i,n) for(ll i=0;i<n;++i)
#define RREP(i,n) for(ll i=n-1;i>=0;--i)
#define FOR(i,m,n) for(ll i=m;i<n;++i)
#define RFOR(i,m,n) for(ll i=n-1;i>=m;--i)
#define ALL(v) (v).begin(),(v).end()
#define PB(a) push_back(a)
#define UNIQUE(v) v.erase(unique(ALL(v)),v.end());
#define DUMP(v) REP(aa, (v).size()) { cout << v[a]; if (a != v.size() - 1)cout << " "; else cout << endl; }
#define INF 1000000001ll
#define MOD 1000000007ll
#define EPS 1e-9

const int dx[8] = { 1,1,0,-1,-1,-1,0,1 };
const int dy[8] = { 0,1,1,1,0,-1,-1,-1 };


using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
ll max(ll a, int b) { return max(a, ll(b)); }
ll max(int a, ll b) { return max(ll(a), b); }
ll min(ll a, int b) { return min(a, ll(b)); }
ll min(int a, ll b) { return min(ll(a), b); }
///(?´????????`)(?´????????`)(?´????????`)(?´????????`)(?´????????`)(?´????????`)///

int h, w;
int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	while (1) {
		cin >> w >> h;
		if (!w)break;
		vector<vector<vvi>> v(w, vector<vvi>(h, vvi(w, vi(h, INF))));
		REP(i, 2 * h - 1) {
			if (i % 2 == 0) {
				REP(j, w - 1) {
					cin >> v[j][i / 2][j + 1][i / 2];
					v[j + 1][i / 2][j][i / 2] = v[j][i / 2][j + 1][i / 2];
				}
			}
			else {
				REP(j, w) {
					cin >> v[j][(i - 1) / 2][j][(i + 1) / 2];
					v[j][(i + 1) / 2][j][(i - 1) / 2] = v[j][(i - 1) / 2][j][(i + 1) / 2];
				}
			}
		}
		queue<pii> q;
		q.push({ 0,0 });
		vvi level(w, vi(h, INF));
		level[0][0] = 0;
		while (!q.empty()) {
			auto c = q.front(); q.pop();
			int cx = c.first, cy = c.second;
			REP(i, 4) {
				int nx = cx + dx[i * 2], ny = cy + dy[2 * i];
				if (nx < w&&ny < h&&nx >= 0 && ny >= 0 && v[cx][cy][nx][ny] == 0 && level[nx][ny]==INF) {
					q.push({ nx,ny });
					level[nx][ny] = level[cx][cy] + 1;
				}
			}
		}

		if (level[w - 1][h - 1] == INF)cout << 0 << endl;
		else cout << level[w - 1][h - 1] + 1 << endl;
	}
	return 0;
}