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++: /*
  2テヲツャツ。テ・ツ?ε」ツつーテ」ツδェテ」ツδε」ツδ嘉」ツ?ァテ」ツ?ッテ」ツ?ェテ」ツ?湘・ツ」ツ?」ツ?古・ツ?・テ・ツ環崚」ツ?ィテ」ツ?療」ツ?ヲテ、ツクツ偲」ツ?暗」ツつ嘉」ツつ古」ツつ凝」ツ??
  テ・ツ青?」ツつーテ」ツδェテ」ツδε」ツδ嘉」ツ?ォテ」ツ??」ツ?敕」ツ?禿」ツ?凝」ツつ?テヲツ鳴ケテ・ツ青妥」ツ?敕」ツつ古」ツ?榲」ツつ古」ツ?ォテァツァツサテ・ツ仰陛・ツ渉ッティツδステ」ツ?凝」ツ?ゥテ」ツ??」ツ?凝」ツ?ョテヲツδ?・ツ?アテ」ツつ津ヲツ個?」ツ?淌」ツ?崚」ツつ凝」ツ??
  テ」ツ?づ」ツ?ィテ」ツ?ッテ」ツ?禿」ツ?ョテ」ツつーテ」ツδェテ」ツδε」ツδ嘉」ツつ津」ツつづ」ツ?ィテ」ツ?ォBFSテ」ツつ津」ツ?凖」ツつ凝」ツ??
 */

#include <stdio.h>

// queue begin

#define QUEUE_SIZE 100000

typedef struct _point {
  int x, y;
} point;

point que[QUEUE_SIZE];
int head, tail;

void init() {
  head = tail = 0;
}

void push(point elm) {
  que[tail] = elm;
  tail = (tail+1) % QUEUE_SIZE;
}

point pop() {
  point elm = que[head];
  head = (head+1) % QUEUE_SIZE;
  return elm;
}

int empty() {
  return head == tail;
}

// queue end

#define MAXH 31
#define MAXW 31
#define INF (1<<28)

const int dx[4] = {1,0,-1,0};
const int dy[4] = {0,1,0,-1};
int W, H;

// G[y][x][d]: テ、ツスツ催ァツスツョ(x,y)テ」ツ?凝」ツつ嘉ヲツ鳴ケテ・ツ青租テ」ツ?ォテァツァツサテ・ツ仰陛」ツ?古・ツ渉ッティツδステ」ツ?凝」ツ?ゥテ」ツ??」ツ??
// dテ」ツ?ッテ、ツクツ甘」ツ?ョテゥツ?催・ツ按妖x, dyテ」ツ?ョテヲツキツサテ・ツュツ療」ツ?ォテ・ツッツセテ・ツソツ愿」ツ?療」ツ?ヲテ」ツ??」ツつ凝」ツ??
int G[MAXH][MAXW][4];
int cost[MAXH][MAXW];

int bfs(int sx, int sy, int gx, int gy) {
  int i, j;
  point p = {sx, sy};
  point np;

  if(sx == gx && sy == gy) return 0;

  for(i = 0; i < H; ++i) {
    for(j = 0; j < W; ++j) {
      cost[i][j] = INF;
    }
  }
  cost[sy][sx] = 0;
  init();
  push(p);
  while(!empty()) {
    p = pop();
    for(i = 0; i < 4; ++i) {
      if(G[p.y][p.x][i]) {
        np.x = p.x + dx[i];
        np.y = p.y + dy[i];
        if(cost[np.y][np.x] == INF) {
          push(np);
          cost[np.y][np.x] = cost[p.y][p.x] + 1;
          if(np.x == gx && np.y == gy) {
            return cost[np.y][np.x];
          }
        }
      }
    }
  }
  return INF;
}

int main() {
  int i, j, k, a, ans;
  while(scanf("%d %d", &W, &H) != EOF) {
    if(W == 0 && H == 0) break;
    for(i = 0; i < H; ++i) {
      for(j = 0; j < W; ++j) {
        for(k = 0; k < 4; ++k) {
          G[i][j][k] = 0;
        }
      }
    }
    for(i = 0; i < H*2-1; ++i) {
      if(i % 2 == 0) {
        for(j = 0; j < W-1; ++j) {
          scanf("%d", &a);
          if(a == 0) {
            G[i/2][j][0] = G[i/2][j+1][2] = 1;
          }
        }
      } else {
        for(j = 0; j < W; ++j) {
          scanf("%d", &a);
          if(a == 0) {
            G[i/2][j][1] = G[i/2+1][j][3] = 1;
          }
        }
      }
    }
    ans = bfs(0,0,W-1,H-1);
    if(ans == INF) ans = 0;
    else ++ans;
    printf("%d\n", ans);
  }
  return 0;
}

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

const int dx[4] = {-1,0,1,0};
const int dy[4] = {0,-1,0,1};
#define L 2
#define U 3
#define R 0
#define D 1

int cost[40][40];
int wall[5][40][40];
bool visited[40][40];
int w, h;

int bfs(int sx, int sy, int gx, int gy) {
  fill(cost[0], cost[32], 0);
  fill(visited[0], visited[32], false);
  cost[0][0] = 1;
  
  queue<pair<int, int> > Q;
  Q.push(make_pair(0, 0));
  while(!Q.empty()) {
    pair<int, int> st = Q.front(); Q.pop();
    visited[st.second][st.first] = true;
    
    if(st.first == gx && st.second == gy) {
      return cost[gy][gx];
    }
    
    for(int i=0; i<4; i++) {
      int nx = st.first + dx[i], ny = st.second + dy[i];
      if(0<= nx && nx < w && 0<= ny && ny < h && !visited[ny][nx] && !wall[i][st.second][st.first]) {
	cost[ny][nx] = cost[st.second][st.first] + 1;
	Q.push(make_pair(nx, ny));
      }
    }
  }
  return 0;
}

int main() {
  while(cin >> w >> h && w+h) {
    for(int i=0; i<4; i++) for(int j=0; j<32; j++) for(int k=0; k<32; k++) wall[i][j][k] = 0;
    
    for(int i=0; i<h; i++) {
      wall[R][i][0] = wall[L][i][w-1] = 1;
    }
    for(int i=0; i<w; i++) {
      wall[D][0][i] = wall[U][h-1][i] = 1;
    }
    
    for(int i=0; i<h; i++) {
      for(int j=0; j<w-1; j++) {
	cin >> wall[L][i][j];
	wall[R][i][j+1] = wall[L][i][j];
      }
      if(i < h-1) {
	for(int j=0; j<w; j++) {
	  cin >> wall[U][i][j];
	  wall[D][i+1][j] = wall[U][i][j];
	}
      }
    }

    /*
    for(int i=0; i<h; i++) {
      for(int j=0; j<w; j++) {
	cout << "R: " << wall[R][i][j] << " L: " << wall[L][i][j] << " U: " << wall[U][i][j] << " D: " << wall[D][i][j] << endl;
      }
    }
    */
    
    cout << bfs(0, 0, w-1, h-1) << endl;
    /*
    for(int i=0; i<h; i++) {
      for(int j=0; j<w; j++) 
	cout << cost[i][j] << " "; 
      cout << endl; 
    }
    */
  }
  
  return 0;
}