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<algorithm>
#include<queue>
#include<limits.h>
using namespace std;
int dy[] = { 0, 1, 0, -1 };
int dx[] = { 1, 0, -1, 0 };
static int map[80][80];
static int minPath[80][80];
typedef struct d Data;
struct d
{
	int x;
	int y;
	int count;
};
int main()
{
	int w, h;
	while (cin >> w >> h && w != 0 || h != 0)
	{
		for (int i = 0; i < 80; i++)
		{
			for (int j = 0; j < 80; j++)
			{
				map[i][j] = 0;
			}
		}

		for (int i = 0; i < h + (h - 1); i++)
		{
			for (int j = (i + 1) % 2; j < w + (w - 1); j+=2)
			{
				cin >> map[i][j];
			}
		}
		for (int i = 0; i < h + (h - 1); i++)
		{
			for (int j = 0; j < w + (w - 1); j++)
			{
				minPath[i][j] = INT_MAX;
			}
		}

		int ans = 0;
		queue<Data> q;
		Data first;
		first.x = 0;
		first.y = 0;
		first.count = 1;
		q.push(first);
		minPath[0][0] = 1;
		while (q.size() > 0)
		{
			Data data = q.front(); q.pop();
			if (data.x == w + (w - 1) - 1 && data.y == h + (h - 1) - 1)
			{
				ans = data.count;
				break;
			}

			for (int i = 0; i < 4; i++)
			{
				int nx = data.x + dx[i] * 2;
				int ny = data.y + dy[i] * 2;
				if (nx < 0 || nx >= w + (w - 1) || ny < 0 || ny >= h + (h - 1))continue;
				int px = data.x + dx[i];
				int py = data.y + dy[i];
				if (map[py][px] == 1)continue;
				if (data.count + 1 > minPath[ny][nx])continue;
				Data d;
				d.x = nx;
				d.y = ny;
				d.count = data.count + 1;
				minPath[ny][nx] = data.count + 1;
				q.push(d);
			}
		}
		cout << ans << endl;


	}
	return 0;
}

C++: #include<stdio.h>
#include<iostream>
#include<math.h>
#include<algorithm>
#include<string>
#define pi 3.14159
#define Inf 99999
using namespace std;



int w, h, a[59][59];
void dfs(int y, int x, int step);
int main(){
	while(1) {
		cin >> w >> h;
		if(w == 0 && h == 0) break;
		for(int i = 0; i < 2*h-1; i++) {
			for(int j = 0; j < 2*w-1; j++) {
				if(i % 2 == 0 && j % 2 == 0) a[i][j] = Inf;
				else if(i % 2 == 1 && j % 2 == 1) a[i][j] = Inf;
				else cin >> a[i][j];
			}
		}
		a[0][0] = 1;
		if(a[1][0] == 0) dfs(2, 0, 1);
		if(a[0][1] == 0) dfs(0, 2, 1);
		if(a[2*h-2][2*w-2] == Inf) cout << 0 <<endl;
		else cout << a[2*h-2][2*w-2] <<endl;
	}
	return 0;
}

void dfs(int y, int x, int step) {
	if(y < 0 || x < 0 || y >= 2*h-1 || x >= 2*w-1) return;
	if(step >= a[y][x]) return;
	else {
		step++;
		a[y][x] = step;
		if(y+1 < 2*h-1) { 
			if(a[y+1][x] == 0) dfs(y+2, x, step);
		}
		if(x + 1 < 2*w-1) {
			if(a[y][x+1] == 0) dfs(y, x+2, step);
		}
		if(y - 1 >= 0) {
			if(a[y-1][x] == 0) dfs(y-2, x, step);
		}
		if(x - 1 >= 0) {
			if(a[y][x-1] == 0) dfs(y, x-2, step);
		}
	}
	return;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i=0; i < (int)(n); i++)
using ull = unsigned long long;
using ll = long long;

struct pos {
    int x, y;
};
vector<pos> DXY = {{-1, 0}, {1, 0}, {0, -1}, {0, 1}};
int route[40][40];

void maze(int W, int H) {
    int Y[W][H], T[W][H];
    string S;
    rep(k, 2*H-1) {
        int hk = k / 2;
        if (k%2==0) {
            rep(wk, W - 1) cin >> Y[wk][hk];
        } else {
            rep(wk, W) cin >> T[wk][hk];
        }
    }

    rep(x, W) rep(y, H) route[x][y] = 0;

    queue<pos> que;
    que.push({0, 0});
    route[0][0] = 1;

    while (!que.empty()) {
        pos now = que.front();
        que.pop();

        for (auto dxy: DXY) {
            int nx = now.x + dxy.x, ny = now.y + dxy.y;
            if (nx < 0 || nx >= W || ny < 0 || ny >= H) continue;
            if (route[nx][ny] == 0) {
                bool ok = true;
                if (abs(dxy.x) == 1) {
                    if (Y[min(nx, now.x)][now.y] == 1) ok = false;
                } else if (abs(dxy.y) == 1){
                    if (T[now.x][min(ny, now.y)] == 1) ok = false;
                }

                if (ok) {
                    route[nx][ny] = route[now.x][now.y] + 1;
                    que.push({nx, ny});
                }
            }
        }
    }

    cout << route[W-1][H-1] << endl;
}

int main() {
    int w, h;
    while (cin >> w >> h, w || h) {
        maze(w, h);
    }

    return 0;
}