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 <vector>
#include <algorithm>
#include <set>
#include <queue>
#include <stack>
#include <string>
#include <map>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>

#define rep(i, n) for(int i = 0; i < n; i ++)
#define ALL(T) T.begin(), T.end()
#define mp make_pair
#define pb push_back
#define MEMSET(v, s) memset((v), s, sizeof(v))
#define X first
#define Y second

using namespace std;

typedef pair<int, int> pii;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<string> vs;

const int INF = 1 << 24;
const int N = 50;

int w, h;
int tate[N][N];
int yoko[N][N];
int m[N][N];

int main(void){
    while(cin >> w >> h, w){
        MEMSET(tate, 1);
        MEMSET(yoko, 1);
        MEMSET(m, 0);

        rep(y, h){
            rep(x, w - 1) cin >> tate[y][x + 1];
            if(y != h - 1) rep(x, w) cin >> yoko[y + 1][x];
        }

        queue<pii> q;
        q.push(mp(0, 0));
        m[0][0] = 1;
        while(!q.empty()){
            pii curP = q.front(); q.pop();
            if(curP == mp(w - 1, h - 1)) break;

            if(!tate[curP.Y][curP.X] && !m[curP.Y][curP.X - 1]) q.push(mp(curP.X - 1, curP.Y)), m[curP.Y][curP.X - 1] = m[curP.Y][curP.X] + 1;
            if(!tate[curP.Y][curP.X + 1] && !m[curP.Y][curP.X + 1]) q.push(mp(curP.X + 1, curP.Y)), m[curP.Y][curP.X + 1] = m[curP.Y][curP.X] + 1;
            if(!yoko[curP.Y][curP.X] && !m[curP.Y - 1][curP.X]) q.push(mp(curP.X, curP.Y - 1)), m[curP.Y - 1][curP.X] = m[curP.Y][curP.X] + 1;
            if(!yoko[curP.Y + 1][curP.X] && !m[curP.Y + 1][curP.X]) q.push(mp(curP.X, curP.Y + 1)), m[curP.Y + 1][curP.X] = m[curP.Y][curP.X] + 1;
        }

        cout << m[h - 1][w - 1] << endl;
    }

    return 0;
}

C++: #include <iostream>
#include <queue>

using namespace std;

struct Point {
  int x, y, dist;
};

int main() {
  int w, h;
  while(1) {
    cin >> w >> h;
    int lr[h][w], td[h][w];
    if(w == 0 && h == 0) break;
    for(int i = 0; i < h; i++) {
      for(int j = 0; j < w-1; j++) {
	cin >> lr[i][j];
      }
      if(i == h-1) break;
      for(int j = 0; j < w; j++) {
	cin >> td[i][j];
      }
    }


    bool visited[h][w];
    for(int i = 0; i < h; i++)
      for(int j = 0; j < w; j++)
	visited[i][j] = false;

    Point p;
    p.x = 0;
    p.y = 0;
    p.dist = 0;

    queue<Point> Q;
    Q.push(p);

    int ans = -1;

    while(!Q.empty()) {
      int d[4][2] = {{1,0}, {0,1}, {-1,0}, {0,-1}};

      p = Q.front();
      Q.pop();
      visited[p.y][p.x] = true;
      if(p.x == w-1 && p.y == h-1) {
	ans = p.dist;
	break;
      }

      for(int i = 0; i < 4; i++) {
	if(lr[p.y][p.x] && i == 0) continue;
	if(p.x-1 >= 0 && lr[p.y][p.x-1] && i == 2) continue;
	if(td[p.y][p.x] && i == 1) continue;
	if(p.y-1 >= 0 && lr[p.y-1][p.x] && i == 3) continue;

	int nx = p.x + d[i][0];
	int ny = p.y + d[i][1];
	if(nx < 0 || nx >= w || ny < 0 || ny >= h) continue;

        if(visited[ny][nx]) continue;

	Point temp;
	temp.x = nx;
        temp.y = ny;
	temp.dist = p.dist + 1;
	Q.push(temp);
	visited[ny][nx] = true;
      }
    }
    if(ans != -1) cout << ans + 1 << endl;
    else cout << 0 << endl;
  }
  return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (n); i++)

using namespace std;

const int inf = 1e8;

int main(){
  int H, W;
  while(cin >> W >> H, H != 0){
    int sz = H* W;
    vector<vector<int>> g(sz, vector<int>(sz, inf));
    rep(i, sz) g[i][i] = 0;

    rep(y, H) {

      rep(x, W - 1){
        int n; cin >> n;
        int l = (n == 1) ? inf : 1;
          g[y * W + x][y * W + (x + 1)] = g[y * W + (x + 1)][y * W + x] = l; 
      }
      if(y == H - 1) break;
      rep(x, W){
        int n; cin >> n;
        int l = (n == 1) ? inf : 1;
          g[y * W + x][(y + 1) * W + x] = g[(y + 1) * W + x][y * W + x] = l;
        
      }
    }
      
   
    vector<vector<int>> a(sz);
    rep(i, sz){
       rep(j, sz){
           if(g[i][j] == 1) a[i].push_back(j);
       }
    }
    
    deque<tuple<int, int>> q;
    vector<int> vis(sz, inf);
    vis[0] = 0;
    q.emplace_back(0, 0);
    while(q.size() > 0){
      int h, s; tie(h, s) = q.back(); q.pop_back();
      for(auto&& k : a[h]){
          if(vis[k] == inf){
              vis[k] = s + 1;
              q.emplace_back(k, s + 1);
          }
      }
    }
    int res = vis[sz - 1] + 1;
    cout << ((res >= inf) ? 0 : res) << endl;
  }
}