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++: #include <iostream>
#include <sstream>
#include <iomanip>
#include <iostream>
#include <sstream>
#include <iomanip>
#include <cmath>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <algorithm>
using namespace std;

void solution(const vector<vector<bool> > wallX, const vector<vector<bool> > wallY)
{
    int goalX = wallX[0].size()-2;
    int goalY = wallX.size()-1;

    queue<int> length;
    queue<int> currX;
    queue<int> currY;
    length.push(1);
    currX.push(0);
    currY.push(0);
    vector<vector<bool> > history(goalY+1, vector<bool>(goalX+1, false));
    history[0][0] = true;

    while(length.size() > 0){
        int x = currX.front();
        int y = currY.front();
        if(x == goalX && y == goalY)
            break;
        if(!wallX[y][x] && !history[y][x-1]){
            length.push(length.front()+1);
            currX.push(x-1);
            currY.push(y);
            history[y][x-1] = true;
        }
        if(!wallX[y][x+1] && !history[y][x+1]){
            length.push(length.front()+1);
            currX.push(x+1);
            currY.push(y);
            history[y][x+1] = true;
        }
        if(!wallY[y][x] && !history[y-1][x]){
            length.push(length.front()+1);
            currX.push(x);
            currY.push(y-1);
            history[y-1][x] = true;
        }
        if(!wallY[y+1][x] && !history[y+1][x]){
            length.push(length.front()+1);
            currX.push(x);
            currY.push(y+1);
            history[y+1][x] = true;
        }

        length.pop();
        currX.pop();
        currY.pop();
    }

    if(length.size() > 0){
        cout << length.front() << endl;
    }else{
        cout << '0' << endl;
    }
}

int main()
{
    for(;;){
        int x, y;
        cin >> x >> y;
        if(x == 0 && y == 0)
            break;

        vector<vector<bool> > wallX(y, vector<bool>(x+1, true));
        vector<vector<bool> > wallY(y+1, vector<bool>(x, true));

        int tmp;
        for(int i=0; i<y-1; ++i){
            for(int j=0; j<x-1; ++j){
                cin >> tmp;
                wallX[i][j+1] = (tmp == 1);
            }
            for(int j=0; j<x; ++j){
                cin >> tmp;
                wallY[i+1][j] = (tmp == 1);
            }
        }

        for(int i=0; i<x-1; ++i){
            cin >> tmp;
            wallX[y-1][i+1] = (tmp == 1);
        }

        solution(wallX, wallY);
    }

    return 0;
}