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: from collections import Counter, deque, defaultdict
import sys
input = sys.stdin.readline
dx = [1, 0, -1, 0]
dy = [0, 1, 0, -1]

def main():
    while True:
        w, h = map(int, input().split())
        if w == 0:
            exit()
        wall = [list(map(int, input().split())) for _ in range(2 * h - 1)]
        check = [[0] * w for _ in range(h)]
        check[0][0] = 1
        q = deque([])
        q.append((0, 0))
        while q:
            y, x = q.popleft()
            for i in range(4):
                ny = y + dy[i]
                nx = x + dx[i]
                if nx < 0 or w-1 < nx or ny < 0 or h-1 < ny:
                    continue
                if check[ny][nx] > 0:
                    continue
                if wall[y + ny][(x + nx) // 2] == 1:
                    continue
                check[ny][nx] = check[y][x] + 1
                q.append((ny,nx))
        print(check[h-1][w-1])


if __name__ == '__main__':
    main()

Python: import sys
from collections import deque


while True:
    w,h=map(int,input().split())
    if w==h==0:
        sys.exit()
    
    #Vert[i][j]=i行目に関して、j列目とj+1列目の間の情報
    #Hori[i][j]=i行目とi+1行目の間に関して、j列目の情報
    Vert=[]
    Hori=[]
    for i in range(2*h-1):
        #縦棒に関する情報
        if i%2==0:
            Vert.append(list(map(int,input().split())))
        #横棒に関する情報
        else:
            Hori.append(list(map(int,input().split())))
    
    #移動可能マスを出力
    def sur(v): #v:tuple
        vx=v[0]
        vy=v[1]
        preE=[(vx-1,vy),(vx+1,vy),(vx,vy-1),(vx,vy+1)]
        E=[]
        if 0<vx:
            if Hori[vx-1][vy]==0:
                E.append((vx-1,vy))
        if vx<h-1:
            if Hori[vx][vy]==0:
                E.append((vx+1,vy))
        if 0<vy:
            if Vert[vx][vy-1]==0:
                E.append((vx,vy-1))
        if vy<w-1:
            if Vert[vx][vy]==0:
                E.append((vx,vy+1))
        return E

    #bfs
    dist=[[0]*w for i in range(h)]
    q=deque()

    dist[0][0]=1
    q.append((0,0))
    while q:
        now=q.popleft()
        for next in sur(now):
            if dist[next[0]][next[1]]>0:
                continue
            q.append(next)
            dist[next[0]][next[1]]=dist[now[0]][now[1]]+1

            if next==(h-1,w-1):
                print(dist[h-1][w-1])
                break
        else:
            continue
        break
    else:
        print(0)

Python: import queue

def step(q, dist, i, j, ni, nj):
    if ni < 0 or ni >= h or nj < 0 or nj >= w: return q
    if dist[ni][nj] == -1:
        q.put((ni, nj))
        dist[ni][nj] = dist[i][j] + 1
    return q


def bfs():
    q = queue.Queue()
    q.put((0, 0))
    dist = [[-1] * w for _ in range(h)]
    dist[0][0] = 1
    while True:
        i, j = q.get()

        if left[i][j] == 0:
            ni, nj = i, j-1
            q = step(q, dist, i, j, ni, nj)
        
        if right[i][j] == 0:
            ni, nj = i, j+1
            q = step(q, dist, i, j, ni, nj)
        
        if up[i][j] == 0:
            ni, nj = i-1, j
            q = step(q, dist, i, j, ni, nj)

        if down[i][j] == 0:
            ni, nj = i+1, j
            q = step(q, dist, i, j, ni, nj)
    
        if q.empty(): break

    return dist[-1][-1]


while True:
    w, h = map(int, input().split())
    if w == 0 and h == 0: break

    # 四方の壁を保持
    left = [[1] * w for _ in range(h)]
    right = [[1] * w for _ in range(h)]
    up = [[1] * w for _ in range(h)]
    down = [[1] * w for _ in range(h)]

    up[0][0] = 0
    down[-1][-1] = 0

    for i in range(2 * h - 1):
        line = list(map(int, input().split()))
        if i % 2 == 0:
            i2 = i // 2
            for j in range(0, w-1):
                right[i2][j] = line[j]
                left[i2][j+1] = line[j]
        else:
            i2 = i // 2
            for j in range(w):
                down[i2][j] = line[j]
                up[i2+1][j] = line[j]
    
    ans = bfs()
    print(ans if ans != -1 else 0)