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 <algorithm>
#include <functional>
#include<vector>
#include<math.h>
#include<bitset>
#include<string.h>
#include<string>
#include <deque>
#include<queue>
#include<map>
#include<type_traits>
using namespace std;
long long int A[105][105];
long long int B[105][105];
int W, H;

void serch(int X,int Y) {
	
	if (X == 2 * W - 1 && Y == 2 * H)return;
	if (A[X + 1][Y] == 1) {
		if (B[X + 1][Y] > B[X][Y] + 1) {
			B[X + 1][Y] = B[X][Y] + 1;
			serch(X + 1, Y);
		}
	}
	
	if (A[X - 1][Y] == 1) {
		if (B[X - 1][Y] > B[X][Y] + 1) {
			B[X - 1][Y] = B[X][Y] + 1;
			serch(X - 1, Y);
		}
	}
	
	if (A[X][Y+1] == 1) {
		
		if (B[X][Y+1] > B[X][Y] + 1) {
			B[X][Y+1] = B[X][Y] + 1;
			serch(X, Y+1);
		}
	}

	if (A[X][Y-1] == 1) {
		if (B[X][Y-1] > B[X][Y] + 1) {
			B[X][Y-1] = B[X][Y] + 1;
			serch(X, Y-1);
		}
	}

	return;
}

int a, b;
int main() {

	cin >> W >> H;


	while (W) {

		for (int i = 0; i < 100; i++) {
			for (int j = 0; j < 100; j++) {
				A[i][j] = 1;
			
			}
		}		
	
		for (int i = 0; i < 100; i++) {
			for (int j = 0; j < 100; j++) {
				B[i][j] = 100000;
			}
		}

		for (int i = 0; i <= 99; i++) {
			A[i][0] = 0;
		}
		for (int i = 0; i <= 99; i++) {
			A[i][2*H] = 0;
		}

		for (int i = 0; i <= 2 * H; i++) {
			A[0][i] = 0;
		}
		for (int i = 0; i <= 2 * H; i++) {
			A[2*W][i] = 0;
		}
		A[1][0] = 1;
		B[1][0] = 0;
		A[2 * W][2 * H] = 1;
		
		//初期化
		for (int i = 1; i <2*H ; i++) {

			if (i % 2 == 1) {
				for (int j = 2; j <2*W ; j+=2) {
					cin >> a;
					if (a == 1) {
						A[j][i] = 0;
						A[j][i + 1] = 0;
						A[j][i - 1] = 0;
					}
				}
			}
			else {
				for (int j = 1; j < 2 * W; j+=2) {
					cin >> a;
					if (a == 1) {
						A[j][i] = 0;
						A[j + 1][i] = 0;
						A[j - 1][i] = 0;
					}
				}
			}
		}

		serch(1, 0);
		if ((B[2 * W - 1][2 * H - 1] + 1) / 2 == 50000) {
			cout << 0 << endl;
		}
		else{
			cout << (B[2 * W - 1][2 * H - 1] + 1) / 2 << endl;
		}
		cin >> W >> H;
		
	}
}