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 <bits/stdc++.h>
# define rep(i, n) for(int i=0, i##_len=(n); i<i##_len; ++i)
# define pb push_back
# define cauto const auto
# define int long long
using namespace std;
template<class Integer>bool IsOdd(Integer &n) { return n & 1; }
template<class Integer>bool IsEven(Integer &n) { return !(n & 1); }
void _cin(){} template <class Head, class... Tail> void _cin(Head&& head, Tail&&... tail){ cin >> head; _cin(forward<Tail>(tail)...); }
#define Cin(Type, ...) Type __VA_ARGS__; _cin(__VA_ARGS__)
void Print() { cout << endl; }
template <class Head, class... Tail> void Print(Head&& head, Tail&&... tail) { cout << head; if (sizeof...(tail) != 0) cout << " "; Print(forward<Tail>(tail)...); }
template <class Type> void Print(vector<Type> &vec) { for (auto& a : vec) { cout << a; if (&a != &vec.back()) cout << " "; } cout << endl; }
template <class Type> void Print(vector<vector<Type>> &df) { for (auto& vec : df) { Print(vec); } }

static const int dx[4] = {1, 0, -1, 0};
static const int dy[4] = {0, 1, 0, -1};
static const vector<pair<int, int>> dydx = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};

int W, H;

bool read()
{
    cin >> W >> H;
    return not (W == 0 and H == 0);
}

bool read(vector<vector<int>>& G)
{
    rep (y, 2*H - 1)
    {
        rep (x, IsEven(y) ? W - 1 : W)
        {
            Cin(int, v);
            if (v == 0) // 壁なし
            {
                int now = y/2*W + x;
                int nxt = now + 1*IsEven(y) + W*IsOdd(y);
                G[now].pb(nxt);
                G[nxt].pb(now);
            }
        }
    }
    return true;
}

signed main()
{
    while (read())
    {
        vector<vector<int>> G(H*W);
        read(G);
        const int entry = 0;
        const int exit = H*W - 1;

        queue<int> que;
        vector<int> d(W*H, -1);
        que.push(entry);
        d[entry] = 0;
        while (not que.empty())
        {
            int now = que.front(); que.pop();
            if (now == exit) break;
            for (cauto& nxt : G[now])
            {
                if (d[nxt] > 0) continue;
                d[nxt] = d[now] + 1;
                que.push(nxt);
            }
        }
        Print(d[exit] + 1);
    }

    return 0;
}

C++: #include<stdio.h>
#include<iostream>
#include<math.h>
#include<algorithm>
#include<string>
#include<utility>
#include<queue>
#define pi 3.14159
#define Inf (int)pow(2., 20.)

using namespace std;
typedef std::pair<int, int> mypair;
int w, h, a[59][59];
queue<mypair> qu;
void bfs(int y, int x);

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[0][1] == 0) {
			qu.push(mypair(0, 2));
			a[0][2] = 2;
		}
		if(a[1][0] == 0) {
			qu.push(mypair(2, 0));
			a[2][0] = 2;
		}
		if(qu.empty() == false) bfs(qu.front().first, qu.front().second);
		if(a[2*h-2][2*w-2] == Inf) cout << 0 <<endl;
		else cout << a[2*h-2][2*w-2] <<endl;
		for(int i = 0; i*2 < 2*h-1; i++) {
			for(int j = 0; j*2 < 2*w-1; j++) {
				cout << a[i*2][j*2] << " " ;
			}
			cout << endl;
		}
	}
	return 0;
}

void bfs(int y, int x) {
	qu.pop();
	
	if(y == 2*h-2 && x == 2*w-2) return;
	if(x + 1 < 2*w-1) {
		if(a[y][x+1] == 0 && a[y][x+2] > a[y][x] + 1) {
			qu.push(mypair(y, x+2));
			a[y][x+2] = a[y][x] + 1;
		}
	}
	if(y+1 < 2*h-1) { 
		if(a[y+1][x] == 0 && a[y+2][x] > a[y][x] + 1) {
			qu.push(mypair(y+2, x));
			a[y+2][x] = a[y][x] + 1;
		}
	}
	if(y - 1 >= 0) {
		if(a[y-1][x] == 0 && a[y-2][x] > a[y][x] + 1) {
			qu.push(mypair(y-2, x));
			a[y-2][x] = a[y][x] +1;
		}
	}
	if(x - 1 >= 0) {
		if(a[y][x-1] == 0 && a[y][x-2] > a[y][x] + 1) {
			qu.push(mypair(y, x-2));
			a[y][x-2] = a[y][x] + 1;
		}
	}
	if(qu.empty() == false) bfs(qu.front().first, qu.front().second);
	return;
}