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<cstdio>
#include<queue>
using namespace std;
typedef pair<int, int> P;

int w, h;
int yoko[30][29], tate[29][30];
bool used[30][30];
int counter[30][30];

bool isOut(int x, int y) {
  if (x < 0 || y < 0 || x >= w || y >= h) return true;
  return false;
}

int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};

int main() {
  while (1) {
    scanf("%d%d", &w, &h);
    if (w == 0) break;
    for (int i = 0; i < h; i++) for (int j = 0; j < w; j++) used[i][j] = false, counter[i][j] = 0;
    for (int i = 0; i < h; i++) {
      for (int j = 0; j < w - 1; j++) scanf("%d", &yoko[i][j]);
      if (i == h - 1) break;
      for (int j = 0; j < w; j++) scanf("%d", &tate[i][j]);
    }
    queue<P> que;
    que.push(P(0, 0));
    used[0][0] = true;
    counter[0][0] = 1;
    while (!que.empty()) {
      P p = que.front(); que.pop();
      int x = p.first, y = p.second;
      for (int i = 0; i < 4; i++) {
        int nx = x + dx[i], ny = y + dy[i];
        if (isOut(nx, ny) || used[ny][nx]) continue;
        if (i == 0 && yoko[y][x] == 1) continue;
        if (i == 1 && tate[y][x] == 1) continue;
        if (i == 2 && yoko[y][x-1] == 1) continue;
        if (i == 3 && tate[y-1][x] == 1) continue;
        que.push(P(nx, ny));
        used[ny][nx] = true;
        counter[ny][nx] = counter[y][x] + 1;
      }
      if (used[h - 1][w - 1]) break;
    }
    printf("%d\n", counter[h - 1][w - 1]);
  }
}

C++: #include "bits/stdc++.h"
using namespace std;
#ifdef _DEBUG
#include "dump.hpp"
#else
#define dump(...)
#endif

//#define int long long
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define all(c) begin(c),end(c)
const int INF = sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = (int)(1e9) + 7;
const double PI = acos(-1);
const double EPS = 1e-9;
template<class T> bool chmax(T &a, const T &b) { if (a < b) { a = b; return true; } return false; }
template<class T> bool chmin(T &a, const T &b) { if (a > b) { a = b; return true; } return false; }

int dp[40][40][40][40];
signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int w, h;
	while (cin >> w >> h, w&&h) {
		memset(dp, 0x3f, sizeof(dp));
		rep(i, 0, h)rep(j, 0, w)dp[i][j][i][j] = 0;
		rep(i, 0, 2 * h - 1) {
			if (i % 2 == 0) {
				rep(j, 0, w - 1) {
					int x; cin >> x;
					// i/2 j,j+1
					dp[i / 2][j][i / 2][j + 1] = (x ? INF : 1);
					dp[i / 2][j + 1][i / 2][j] = (x ? INF : 1);
				}
			}
			else {
				rep(j, 0, w) {
					int x; cin >> x;
					// i/2 i/2+1 j
					dp[i / 2][j][i / 2 + 1][j] = (x ? INF : 1);
					dp[i / 2 + 1][j][i / 2][j] = (x ? INF : 1);
				}
			}
		}
		rep(a, 0, h)rep(b, 0, w)rep(i, 0, h)rep(j, 0, w)rep(x, 0, h)rep(y, 0, w) {
			chmin(dp[i][j][x][y], dp[i][j][a][b] + dp[a][b][x][y]);
		}
		int ans = dp[0][0][h - 1][w - 1];
		cout << (ans == INF ? 0 : ans+1) << endl;
	}
	return 0;
}