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 <cstdlib>
#include <cmath>
#include <cstring>
#include <map>
#include <utility>
#include <set>
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>

using namespace std;
typedef long long LL;
typedef pair<int, int> PII;
typedef pair<int, PII> PIP;
typedef complex<double> P;
static const double EPS = 1e-8;
static const int INF = (int)1e8;

#define FOR(i,k,n) for (int i=(k); i<(int)(n); ++i)
#define REP(i,n) for (int i=0; i<(int)(n); ++i)
#define FOREQ(i,k,n) for (int i=(k); i<=(int)(n); ++i)
#define FORIT(i,c) for(__typeof((c).begin())i=(c).begin();i!=(c).end();++i)
#define FIND(m,w) ((m).find(w)!=(m).end())
bool wall[100][100];
bool arrive[100][100];
int W,H;
bool inmaze(int x, int y){
  return (x>=0&x<W&&y>=0&&y<H);
}

int main(void){
  while(cin>>W>>H){
    memset(arrive,0,sizeof(arrive));
    if(!W&&!H) break;
    REP(i,2*H-1){
      REP(j,W-(i+1)%2){
        cin>>wall[i][j];
      }
    }
    queue<PIP> que;
    que.push(PIP(0,PII(0,0)));
    bool find = false;
    while(!que.empty()){
      PIP pip = que.front(); que.pop();
      PII p = pip.second;
      int x = p.first;
      int y = p.second;
      if(arrive[y][x]) continue;
      arrive[y][x] = true;
      if(p == PII(W-1,H-1)){
        cout<<pip.first+1<<endl;
        find = true;
        break;
      }
      int nx,ny;
      nx = x + 1; ny = y;
      if(inmaze(nx,ny)&&!wall[y*2][x]){
        que.push(PIP(pip.first+1,PII(nx,ny)));
      }
      nx = x - 1; ny = y;
      if(inmaze(nx,ny)&&!wall[ny*2][nx]){
        que.push(PIP(pip.first+1,PII(nx,ny)));
      }
      nx = x; ny = y+1;
      if(inmaze(nx,ny)&&!wall[y*2+1][x]){
        que.push(PIP(pip.first+1,PII(nx,ny)));
      }
      nx = x; ny = y-1;
      if(inmaze(nx,ny)&&!wall[ny*2+1][nx]){
        que.push(PIP(pip.first+1,PII(nx,ny)));
      }
    }
    if(!find) cout<<"0"<<endl;
  }
  return 0;
}

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

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 = 1000000;
		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;
			}
		}
		/*
		cout << endl;
		cout << n << " " << m << endl;
		for(int i=0; i < m*2-1; i++){
			for(int j=0; j < n*2-1; j++){
				cout << field[i][j];
			}
			cout << endl;
		}
		*/
		dfs(0, 0, 0);

		if(ans == 1000000) cout << 0 << endl;
		else cout << ans << endl;
	}

}