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 <queue>
#include <algorithm>
#include <utility> // pair
using namespace std;

struct Point {
  int x, y;
};

int main() {
  const int M = 30;
  int w, h;
  while (scanf("%d%d", &w, &h) != EOF && w && h) {
    // 隣接リスト作成
    int d;
    vector<Point> V[M][M];
    for (int i=0; i<h; i++) {
      for (int j=0; j<w-1; j++) {
	scanf("%d", &d);
	if (d == 0) {
	  Point p = { i, j+1 };
	  V[i][j].push_back(p);
	  // cerr << "Connect (" << i << "," << j << ") and (" << i << "," << j+1 << ")" << endl;
	  p = { i, j };
	  V[i][j+1].push_back(p);
	}
      }
      if (i != h-1) {
	for (int j=0; j<w; j++) {
	  scanf("%d", &d);
	  if (d == 0) {
	    Point p = { i+1, j };
	    V[i][j].push_back(p);
	    // cerr << "Connect (" << i << "," << j << ") and (" << i+1 << "," << j << ")" << endl;
	    p = { i, j };
	    V[i+1][j].push_back(p);
	  }
	}
      }
    }
    // 幅優先探索
    queue<pair<Point,int>> Q;
    bool visited[M][M];
    fill(&visited[0][0], &visited[0][0]+M*M, false);
    Point p = {0, 0};
    Q.push(make_pair(p, 0));
    while (! Q.empty()) {
      p = Q.front().first;
      // cerr << "Visiting (" << p.x << "," << p.y << ")" << endl;
      int count = Q.front().second;
      Q.pop();
      if (! visited[p.x][p.y]) {
	visited[p.x][p.y] = true; // これがないと無限ループ！
	if (p.x == h-1 && p.y == w-1) {
	  printf("%d\n", count+1);
	  goto END;
	}
	for (unsigned int i=0; i<V[p.x][p.y].size(); i++) {
	  Point q = V[p.x][p.y][i];
	  if (! visited[q.x][q.y]) {
	    Q.push(make_pair(q, count+1));
	  }
	}
      }
    }
    printf("0\n");
  END: continue;
  }
}

C++: #include <bits/stdc++.h>
#pragma GCC target("avx")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
using namespace std;
using ll = long long;
using P = pair<int, int>;
template<class T> inline bool chmax(T &a, T b) { if (a<b) {a=b; return 1;} return 0;}
template<class T> inline bool chmin(T &a, T b) { if (b<a) {a=b; return 1;} return 0;}

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

void solve(int w, int h) {
    vector<vector<bool>> can_move_y(h-1, vector<bool>(w, true));
    vector<vector<bool>> can_move_x(h, vector<bool>(w-1, true));

    rep(i, 2*h-1) {
        if (i&1) {
            rep(j, w) {
                int a;
                cin >> a;
                can_move_y[(i-1)/2][j] = !a; 
            }
        } else {
            rep(j, w-1) {
                int a;
                cin >> a;
                can_move_x[i/2][j] = !a; 
            }
        }
    }

    queue<P> q;
    vector<vector<int>> dist(h, vector<int>(w, -1));
    q.push(P(0, 0));
    dist[0][0] = 1;

    while (!q.empty()) {
        int y = q.front().first, x = q.front().second;
        q.pop();
        rep(i, 4) {
            int ny = y + dy[i], nx = x + dx[i];
            if (ny < 0 || h <= ny || nx < 0 || w <= nx) continue;
            if (dist[ny][nx] >= 0) continue;
            if (i == 0) {
                // 下に移動
                if (!can_move_y[y][x]) continue;
            }
            if (i == 1) {
                // 上に移動
                if (!can_move_y[y-1][x]) continue;
            }
            if (i == 2) {
                // 右に移動
                if (!can_move_x[y][x]) continue;
            }
            if (i == 3) {
                // 左に移動
                if (!can_move_x[y][x-1]) continue;
            }
            q.push(P(ny, nx));
            dist[ny][nx] = dist[y][x] + 1;
        }
    }
    if (dist[h-1][w-1] == -1) cout << 0 << endl;
    else cout << dist[h-1][w-1] << endl;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    while (true) {
        int w, h;
        cin >> w >> h;
        if (w == 0 && h == 0) return 0;
        else solve(w, h);
    }
}