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: #!/usr/bin/env python3

from pprint import pprint
from collections import deque
import sys

sys.setrecursionlimit(10 ** 6)
input = sys.stdin.buffer.readline


def adj(i, j):
    up, down = [i - 1, j], [i + 1, j]
    left, right = [i, j - 1], [i, j + 1]
    res = []
    for i_next, j_next in up, down, left, right:
        if 0 <= i_next < height and 0 <= j_next < width:
            if [i_next, j_next] == left:
                if walls[i * 2][j - 1] == 0:
                    res.append([i_next, j_next])
            elif [i_next, j_next] == right:
                if walls[i * 2][j] == 0:
                    res.append([i_next, j_next])
            elif [i_next, j_next] == up:
                if walls[2 * i - 1][j] == 0:
                    res.append([i_next, j_next])
            else:
                if walls[2 * i + 1][j] == 0:
                    res.append([i_next, j_next])
    return res


def bfs(que, dist):
    while len(que) > 0:
        i, j = que.popleft()
        for i_next, j_next in adj(i, j):
            if dist[i_next][j_next] == -1:
                dist[i_next][j_next] = dist[i][j] + 1
                que.append([i_next, j_next])
    return dist


while True:
    width, height = map(int, input().split())
    if width == 0 and height == 0:
        break
    walls = []
    for _ in range(2 * height - 1):
        line = list(map(int, input().split()))
        walls.append(line)
    # pprint(walls)

    maze = [[-1 for j in range(width)] for i in range(height)]
    que = deque()
    dist = [[-1 for j in range(width)] for i in range(height)]

    start = [0, 0]
    que.append(start)
    dist[0][0] = 0

    dist = bfs(que, dist)
    print(dist[height - 1][width - 1] + 1)

Python: from collections import deque
while True:
    W,H = map(int, input().split())
    if W == 0: break
    es = [[] for i in range(W*H)]
    for y in range(H):
        walls_h = list(map(int, input().split()))
        for x in range(W-1):
            if walls_h[x]: continue
            es[y*W + x].append(y*W + x+1)
            es[y*W + x+1].append(y*W + x)
        if y == H-1: break
        walls_v = list(map(int, input().split()))
        for x in range(W):
            if walls_v[x]: continue
            es[y*W + x].append((y+1)*W + x)
            es[(y+1)*W + x].append(y*W + x)
    q = deque([0])
    dist = [0] * (W*H)
    dist[0] = 1
    while q:
        fr = q.popleft()
        for to in es[fr]:
            if dist[to] == 0:
                dist[to] = dist[fr] + 1
                q.append(to)
    print(dist[-1])

Python: # coding: utf-8
while True:
    m,n = map(int,input().split())
    sw = []
    bw = []
    if m == 0 and n == 0:
        break
    for i in range(2*n-1):
        if i % 2 == 0:
            sw.append(list(map(int,input().split())))
        else:
            bw.append(list(map(int,input().split())))
    flag = [[0 for i in range(m)] for j in range(n)]
    l = [[0,0,1]]
    res = 0
    while l:
        bf = l[0]
        l.pop(0)
        if bf[0] == n-1 and bf[1] == m-1:
            res = bf[2]
            break
        flag[bf[0]][bf[1]] = 1
        if 1 <= bf[0] and bw[bf[0]-1][bf[1]] == 0 and flag[bf[0]-1][bf[1]] == 0:
            l.append([bf[0]-1,bf[1],bf[2]+1])
        if bf[1] < m-1 and sw[bf[0]][bf[1]] == 0 and flag[bf[0]][bf[1]+1] == 0:
            l.append([bf[0],bf[1]+1,bf[2]+1])
        if 1 <= bf[1] and sw[bf[0]][bf[1]-1] == 0 and flag[bf[0]][bf[1]-1] == 0:
            l.append([bf[0],bf[1]-1,bf[2]+1])
        if bf[0] < n-1 and bw[bf[0]][bf[1]] == 0 and flag[bf[0]+1][bf[1]] == 0:
            l.append([bf[0]+1,bf[1],bf[2]+1])
    print(res)