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++: //
//  main.cpp
//  AOJ1166
//
//  Created by aki33524 on 2014/07/06.
//  Copyright (c) 2014年 aki33524. All rights reserved.
//

#include <iostream>
#include <queue>
#include <vector>
using namespace std;

typedef pair<int, int> P;
const int INF = 1e8;
int dh[] = {1, 0, -1, 0};
int dw[] = {0, 1, 0, -1};

int W, H;
int d[50][50];
int maze[50][50];

void solve(){
    queue<P> que;
    for(int h=0; h<H; h++)
        for(int w=0; w<W; w++)
            d[h][w] = INF;
    
    que.push(P(0, 0));
    d[0][0] = 1;
    
    while(!que.empty()){
        P p = que.front(); que.pop();
        for(int i=0; i<4; i++){
            int nh = p.first + dh[i];
            int nw = p.second + dw[i];
            if(0<=nh&&nh<H && 0<=nw&&nw<W && !(maze[p.first][p.second]&(1<<i)) && d[nh][nw]==INF){
                que.push(P(nh, nw));
                d[nh][nw] = d[p.first][p.second] + 1;
            }
        }
    }
    cout << (d[H-1][W-1]==INF ? 0 : d[H-1][W-1]) << endl;
}

int main(int argc, const char * argv[]){
    while(cin>>W>>H, W|H){
        memset(maze, 0, sizeof(maze));
        
        for(int h=0; h<H*2-1; h++){
            if(h%2 == 0){
                for(int w=0; w<W-1; w++){
                    int a;
                    cin >> a;
                    if(a){
                        maze[h/2][w] |= (1<<1);
                        maze[h/2][w+1] |= (1<<3);
                    }
                }
            }else{
                for(int w=0; w<W; w++){
                    int a;
                    cin >> a;
                    if(a){
                        maze[h/2][w] |= (1<<0);
                        maze[h/2+1][w] |= (1<<2);
                    }
                }
            }
        }
        solve();
    }
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define REP(i, n) for (int i = 0; i < (int)(n); i++)
typedef long long ll;
typedef pair<int, int> P;
const int INF = 1e6;
int main() {
  int h, w;
  while (cin >> w) {
    cin >> h;
    if (h == 0 && w == 0) return 0;
    vector<vector<bool>> A(h * 2 - 1);
    REP(i, w - 1) {
      bool t;
      cin >> t;
      A[0].push_back(t);
    }
    REP(i, h - 1) {
      bool t;
      int id = i * 2 + 1;
      REP(i, w) {
        cin >> t;
        A[id].push_back(t);
      }
      REP(i, w - 1) {
        cin >> t;
        A[id + 1].push_back(t);
      }
    }
    vector<vector<int>> dis(h, vector<int>(w, -INF));
    queue<P> que;
    que.push(P(0, 0));
    dis[0][0] = 1;
    while (!que.empty()) {
      P p = que.front();
      que.pop();
      int x = p.second, y = p.first;
      if (0 < x) {
        int nx = x - 1, ny = y;
        if (A[y * 2][x - 1] == 0) {
          if (dis[ny][nx] == -INF) {
            dis[ny][nx] = dis[y][x] + 1;
            que.push(P(ny, nx));
          }
        }
      }
      if (x < w - 1) {
        int nx = x + 1, ny = y;
        if (A[y * 2][x] == 0) {
          if (dis[ny][nx] == -INF) {
            dis[ny][nx] = dis[y][x] + 1;
            que.push(P(ny, nx));
          }
        }
      }
      if (0 < y) {
        int nx = x, ny = y - 1;
        if (A[y * 2 - 1][x] == 0) {
          if (dis[ny][nx] == -INF) {
            dis[ny][nx] = dis[y][x] + 1;
            que.push(P(ny, nx));
          }
        }
      }
      if (y < h - 1) {
        int nx = x, ny = y + 1;
        if (A[y * 2 + 1][x] == 0) {
          if (dis[ny][nx] == -INF) {
            dis[ny][nx] = dis[y][x] + 1;
            que.push(P(ny, nx));
          }
        }
      }
    }
    if (dis[h - 1][w - 1] == -INF) {
      cout << 0 << endl;
    } else {
      cout << dis[h - 1][w - 1] << endl;
    }
  }
}