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 <cstdio>
#include <iostream>
#include <string>
#include <vector>
#include <sstream>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <cmath>
#include <cstdlib>
#include <cstring>
#include <typeinfo>
#include <numeric>
#include <functional>
#include <unordered_map>
#include <bitset>


using namespace std;
using ll = long long;
using ull = unsigned long long;

const ll INF = 1e16;
const ll MOD = 1e9 + 7;

#define REP(i, n) for(int i = 0; i < n; i++)




int w, h, gy, gx, m[65][65], d[65][65];

void bfs(int y, int x, int k){
    if(y == gy && x == gx)return;
    
    if(x < gx && m[y][x + 1] == 0 && k + 1 < d[y][x + 2]){
        d[y][x + 2] = k + 1;
        bfs(y, x + 2, k + 1);
    }
    if(0 < x && m[y][x - 1] == 0 && k + 1 < d[y][x - 2]){
        d[y][x - 2] = k + 1;
        bfs(y, x - 2, k + 1);
    }
    if(y < gy && m[y + 1][x] == 0 && k + 1 < d[y + 2][x]){
        d[y + 2][x] = k + 1;
        bfs(y + 2, x, k + 1);
    }
    if(0 < y && m[y - 1][x] == 0 && k + 1 < d[y - 2][x]){
        d[y - 2][x] = k + 1;
        bfs(y - 2, x, k + 1);
    }
}

int main() {
    cin >> w >> h;
    while(w != 0 || h != 0){
        REP(i, 65){
            REP(j, 65){
                m[i][j] = 0;
                d[i][j] = 1e9;
            }
        }
        REP(i, h * 2 - 1){
            if(i % 2 == 0){
                REP(j, w - 1){
                    cin >> m[i][j * 2 + 1];
                }
            }
            else{
                REP(j, w){
                    cin >> m[i][j * 2];
                }
            }
        }
        
        gy = h * 2 - 2;
        gx = w * 2 - 2;
        d[0][0] = 0;
        bfs(0, 0, 1);
        
        cout << ((d[gy][gx] != 1e9)? d[gy][gx] : 0) << endl;
        
        cin >> w >> h;
    }
}

C++: #include<iostream>
using namespace std;

const double inf = (int)1e8;

int field[150][150];
int dx[4] = {2, 0, -2, 0};
int dy[4] = {0, 2, 0, -2};
int ans;
int n, m;

void dfs(int x, int y, int count){
	if(0 <= x && x < m*2-1 && 0 <= y && y < n*2-1 && field[x][y] == 0){
		count++;
		field[x][y] = 1;
		if(m*2-2 == x && n*2-2 == y){
			if(count < ans) ans = count;
			count--;
			return;
		}
		for(int i=0; i < 4; i++){
			if(field[x+dx[i]/2][y+dy[i]/2] == 0) dfs(x+dx[i], y+dy[i], count);
		}
		count--;
	}
}

int main(){
	int state;
	while(cin >> n >> m, n || m){
		ans = inf;
		for(int i=0; i < 150; i++){
			for(int j=0; j < 150; j++){
				field[i][j] = 0;
			}
		}
		for(int i=0; i < m*2-1; i++){
			for(int j=0; j < n; j++){
				if(i % 2 == 0 && j == n-1) break;
				cin >> state;
				if(i % 2 == 0)field[i][j*2+1] = state;
				else if(i % 2 == 1) field[i][j*2] = state;
			}
		}

        dfs(0, 0, 0);

        cout << (ans==inf?0:ans) << endl;
	}
}