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
input = sys.stdin.readline
sys.setrecursionlimit(10000000)
from collections import deque


def bfs(scores, right_bars, bottom_bars, start_point, goal_point):
    queue = deque([start_point])
    while queue:
        now_point = queue.popleft()
        mv = [[-1, 0], [0, -1], [1, 0], [0, 1]]
        if now_point[0] == 0:
            # 上はなし
            mv.remove([-1, 0])
        if now_point[0] >= h - 1:
            # 下はなし
            mv.remove([1, 0])
        if now_point[1] == 0:
            # 左はなし
            mv.remove([0, -1])
        if now_point[1] >= w - 1:
            # 右はなし
            mv.remove([0, 1])
        for next_position in mv:
            next_point = [now_point[0] + next_position[0],
                          now_point[1] + next_position[1]]
            if next_position == [-1, 0]:  # 上　
                if bottom_bars[next_point[0]][next_point[1]] == 0 and scores[now_point[0]][now_point[1]] + 1 < scores[next_point[0]][next_point[1]]:
                    queue.append(next_point)
                    scores[next_point[0]][next_point[1]
                                          ] = scores[now_point[0]][now_point[1]] + 1
            if next_position == [0, -1]:  # 左
                if right_bars[next_point[0]][next_point[1]] == 0 and scores[now_point[0]][now_point[1]] + 1 < scores[next_point[0]][next_point[1]]:
                    queue.append(next_point)
                    scores[next_point[0]][next_point[1]
                                          ] = scores[now_point[0]][now_point[1]] + 1
            if next_position == [1, 0]:  # 下
                # print('++++++++++++++++')
                # print(scores)
                # print(right_bars)
                # print(now_point[0], now_point[1])
                # print(next_point[0], next_point[1])
                if bottom_bars[now_point[0]][now_point[1]] == 0 and scores[now_point[0]][now_point[1]] + 1 < scores[next_point[0]][next_point[1]]:
                    queue.append(next_point)
                    scores[next_point[0]][next_point[1]
                                          ] = scores[now_point[0]][now_point[1]] + 1
            if next_position == [0, 1]:  # 右
                if right_bars[now_point[0]][now_point[1]] == 0 and scores[now_point[0]][now_point[1]] + 1 < scores[next_point[0]][next_point[1]]:
                    queue.append(next_point)
                    scores[next_point[0]][next_point[1]
                                          ] = scores[now_point[0]][now_point[1]] + 1
    # print(scores)
    if scores[goal_point[0]][goal_point[1]] == (len(scores[0]) * len(scores)):
        return 0
    return scores[goal_point[0]][goal_point[1]]


costs = []
while True:
    w, h = map(int, input().split())
    if [w, h] == [0, 0]:
        break
    scores = [[w * h for _ in range(w)] for _ in range(h)]
    scores[0][0] = 1
    right_bars = []
    bottom_bars = []
    for _ in range(h - 1):
        right_bar = list(map(int, input().split()))
        bottom_bar = list(map(int, input().split()))
        right_bars.append(right_bar)
        bottom_bars.append(bottom_bar)
    right_bar = list(map(int, input().split()))
    right_bars.append(right_bar)
    start_point = [0, 0]
    goal_point = [h - 1, w - 1]
    cost = bfs(scores, right_bars, bottom_bars, start_point, goal_point)
    costs.append(cost)
for cost in costs:
    print(cost)