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)
}

Python: import sys
import math
import string
import fractions
import random
from operator import itemgetter
import itertools
from collections import deque
import copy
import heapq
import bisect

MOD = 10 ** 9 + 7
INF = float('inf')
input = lambda: sys.stdin.readline().strip()
closed = [0, 0, 0, 0]
sys.setrecursionlimit(10 ** 8)

while True:
    w, h = map(int, input().split())
    if w == h == 0:
        break
    info = [[closed for _ in range(w + 2)]]  # 上左下右
    for _ in range(h):
        info.append([closed] + [[1] * 4 for _ in range(w)] + [closed])
    info.append([closed for _ in range(w + 2)])
    for i in range(1, w + 1):  # 0＝壁, 1=なにもない
        info[0][i][0] = 0
        info[-1][i][2] = 0
    for i in range(1, h + 1):
        info[i][0][1] = 0
        info[i][-1][3] = 0
    for i in range(1, h + 1):
        vertical_wall = list(map(int, input().split()))
        for j in range(1, w):
            if vertical_wall[j-1] == 1:
                info[i][j][3] = 0
                info[i][j + 1][1] = 0
        if i < h:
            horizontally_wall = list(map(int, input().split()))
            for j in range(1, w + 1):
                if horizontally_wall[j-1] == 1:
                    info[i][j][2] = 0
                    info[i + 1][j][0] = 0
    stack = deque([[1, 1, 1]])
    info[1][1] = closed
    while len(stack) > 0:
        y, x, dis = stack.popleft()
        if y == h and x == w:
            print(dis)
            break
        if info[y][x + 1][1] == 1:
            info[y][x + 1] = closed
            stack.append([y, x + 1, dis + 1])
        if info[y][x - 1][3] == 1:
            info[y][x - 1] = closed
            stack.append([y, x - 1, dis + 1])
        if info[y + 1][x][0] == 1:
            info[y + 1][x] = closed
            stack.append([y + 1, x, dis + 1])
        if info[y - 1][x][2] == 1:
            info[y - 1][x] = closed
            stack.append([y - 1, x, dis + 1])
        if len(stack) == 0:
            print(0)
            break

Python: from collections import deque

while True:
  w,h = map(int,input().split())
  ww = w*2-1
  hh = h*2-1
  if w == 0:
    break
  field = [input() for _ in range(hh)]
  d = [[0]*(ww) for _ in range(hh)]
  q = deque()
  q.append([0,0])
  dmov = [(-1,0),(1,0),(0,-1),(0,1)]
  d[0][0] = 1
  
  while len(q) > 0:
    node = q.popleft()
    x = node[0]
    y = node[1]
    c = d[y][x]
    for i,j in dmov:
      xx = x+i
      yy = y+j
      xxx = xx+i
      yyy = yy+j
      if 0<=xx<ww and 0<=yy<hh:
        if d[yyy][xxx] == 0 and field[yy][xx] == "0":
          d[yyy][xxx] = c+1
          q.append([xxx,yyy])
  print(d[hh-1][ww-1])