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 <cstring>
#include <algorithm>
#include <cstdio>
#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <complex>
#include <queue>
#include <stack>
#include <string>
#include <cmath>
#include <bitset>

#define rep(i,a) for(int i = 0;i < (a); i++)
#define repi(i,a,b) for(int i = (a); i < (b); i++)
#define repd(i,a,b) for(int i = (a); i >= (b); i--)
#define repit(i,a) for(__typeof((a).begin()) i = (a).begin(); i != (a).end(); i++)
#define all(u) (u).begin(),(u).end()
#define rall(u) (u).rbegin(),(u).rend()
#define UNIQUE(u) (u).erase(unique(all(u)),(u).end())
#define pb push_back
#define mp make_pair
#define INF 100000000
#define EPS 1e-10
#define PI acos(-1.0)

using namespace std;

typedef long long ll;
typedef vector<int> vi;
int w, h;
const int dx[] = { 0, 1, 0,-1};
const int dy[] = {-1, 0, 1, 0};
int wall[31][31][4];
struct node{
  int x, y, step;
  bool operator<(const node &o) const{
    return step > o.step;
  }
};
int main(){
  while(cin >> w >> h, w||h){
    int a;
    memset(wall, 0, sizeof(wall));
    rep(x, w-1){
      cin >> a;
      if(a) wall[x][0][1] = wall[x][0][3] = true;
    }
    rep(y, h-1){
      rep(x, w){
	cin >> a;
	if(a) wall[x][y][2] = wall[x][y+1][0] = true;
      }
      rep(x, w-1){
	cin >> a;
	if(a) wall[x][y+1][1] = wall[x+1][y+1][3] = true;
      }
    }
    int ans = -1;
    priority_queue<node> pq;
    pq.push((node){0, 0, 0});
    bool done[31][31] = {0};
    while(!pq.empty()){
      int x = pq.top().x;
      int y = pq.top().y;
      int step = pq.top().step;
      pq.pop();
      if(done[x][y]) continue;
      done[x][y] = true;
      //cout << x << " " << y << " " << step << endl;
      if(x == w-1 && y == h-1){
	ans = step;
	break;
      }
      rep(d, 4){
	int nx = x + dx[d];
	int ny = y + dy[d];
	if(!wall[x][y][d] && nx >= 0 && ny >= 0 && nx < w && ny < h){
	  pq.push((node){nx, ny, step+1});
	}
      }
    }
    cout << ans + 1 << endl;
  }
}

C++: #include <iostream>
#include <complex>
#include <sstream>
#include <string>
#include <algorithm>
#include <deque>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <vector>
#include <set>
#include <limits>
#include <cstdio>
#include <cctype>
#include <cmath>
#include <cstring>
#include <cstdlib>
#include <ctime>
using namespace std;
#define REP(i, j) for(int i = 0; i < (int)(j); ++i)
#define FOR(i, j, k) for(int i = (int)(j); i < (int)(k); ++i)
#define P pair<int, int>
#define SORT(v) sort((v).begin(), (v).end())
#define REVERSE(v) reverse((v).begin(), (v).end())
//#define int long long
const int MAX_H = 35;
const int MAX_W = 35;
const int INF = 1e9 + 10;

int W, H;
bool v[MAX_H][MAX_W][4];
int my[] = {-1, 0, 1, 0};
int mx[] = {0, 1, 0, -1};

class C{
  public:
    int y, x, c;
    C(int _y, int _x, int _c){ y = _y; x = _x; c = _c; };
    C(){}
};

int main() {
  while(cin >>W >>H && H){
    REP(i, MAX_H) REP(j, MAX_W) REP(k, 4) v[i][j][k] = true;
    string s;
    getline(cin, s);
    REP(z, 2 * H - 1){
      getline(cin, s);
      if(z % 2){
        for(int i = 0; i < (int)(s.length()); i += 2){
          if(s[i] == '1'){
            v[z / 2][i / 2][2] = false;
            v[z / 2][(i + 1) / 2][0] = false;
          }
        }
      } else{
        for(int i = 1; i < (int)(s.length()); i += 2){
          if(s[i] == '1'){
            v[z / 2][i / 2][1] = false;
            v[z / 2][(i + 1) / 2][3] = false;
          }
        }
      }
    }
    REP(i, H) v[i][0][3] = v[i][W - 1][1] = false;
    REP(i, W) v[0][i][0] = v[H - 1][i][2] = false;
    //debug
    //REP(i, H){
    //  REP(j, W){
    //    cout <<i <<", " <<j <<" | ";
    //    REP(k, 4) cout <<v[i][j][k] <<" ";
    //    cout <<endl;
    //  }
    //}

    queue<C> open;
    open.push(C(0, 0, 1));
    int closed[MAX_H][MAX_W];
    REP(i, MAX_H) REP(j, MAX_W) closed[i][j] = INF;
    while(!open.empty()){
      C now = open.front(); open.pop();
      int y = now.y, x = now.x, c = now.c;
      if(closed[y][x] <= c) continue;
      closed[y][x] = c;
      REP(i, 4) if(v[y][x][i]) open.push(C(y + my[i], x + mx[i], c + 1));
    }
    cout <<(closed[H - 1][W - 1] == INF ? 0 : closed[H - 1][W - 1]) <<endl;
  }
  return 0;
}