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 <cstring>
using namespace std;

struct S {
    int y, x;
    int t;
    S(int y, int x, int t) : y(y), x(x), t(t) {}
};

const int dy[] = {0, 2, 0, -2};
const int dx[] = {2, 0, -2, 0};

int w, h;
int main() {
    while (cin >> w >> h) {
        vector<string> field;
        if (w == 0 && h == 0) break;
        cin.ignore(1024, '\n'); // 1024は適当に選んだ数値. でかけりゃなんでもいい
        for (int i = 0; i < h*2-1; i++) {
            string s;
            getline(cin, s);
            if (i % 2 == 0) s.push_back(' ');
            field.push_back(s);
        }

        bool v[2*h-1][2*w-1];
        memset(v, 0, sizeof(v));
        queue<S> q;
        q.push(S(0, 0, 1));
        bool found = false;
        while (!q.empty()) {
            S p = q.front(); q.pop();
            if (p.y == 2*h-2 && p.x == 2*w-2) {
                cout << p.t << endl;
                found = true;
                break;
            }
            v[p.y][p.x] = true;
            for (int j = 0; j < 4; j++) {
                int ny = p.y + dy[j];
                int nx = p.x + dx[j];
                if (0 <= ny && ny < 2*h-1 && 0 <= nx && nx < 2*w-1
                            && !v[ny][nx] 
                            && field[(ny + p.y) / 2][(nx + p.x) / 2] == '0') {
                    //cout << (ny+p.y)/2 << ',' << (nx+p.x)/2 << ':' << field[(ny + p.y) / 2][(nx + p.x) / 2] << endl;
                    q.push(S(ny, nx, p.t+1));
                }
            }
        }
        if (!found) cout << 0 << endl;
    }
    return 0;
}

C++: // 0704 未完成
// segmentation fault

#include <iostream>
#include <sstream>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <utility>
#include <algorithm>
#include <functional>
#include <cstdio>
#include <cstdlib>


#include <cstring>
#include <cmath>
#include <cctype>

using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n)  FOR(i,0,n)

#define SIZE 50

int dx[] = {1, 0, -1, 0};
int dy[] = {0, 1, 0, -1};
int Height, Width;
int Pass[SIZE][SIZE][SIZE][SIZE];
int Ans;
map<pair<int, int>, int> ansMap; // マスint1までの経路はint2

bool Used[1000][1000];

void search(int h, int w, int cnt) {
  if(h==Height-1 && w==Width-1) {
    Ans = min(Ans, cnt);
    return;
  }
  /*
  if(h<0 || w<0 || Height<=h || Width<=w) {
    return;
  }
  */  

  /*
  else {
    for(int i=0; i<4; i++) {
      //int tmp = ansMap[make_pair(h, w)] +1;
      if(h+dy[i]>=0 && w+dx[i]>=0 && h+dy[i]<Height && w+dx[i]<Width && Pass[h][w][h+dy[i]][w+dx[i]]==0) {
	if(ansMap.find(make_pair(h+dy[i], w+dx[i]))==ansMap.end()) {
	  ansMap.insert(make_pair(pair<int,int>(w+i, h+i), tmp));
	  search(h+dy[i], w+dx[i], cnt+1);
	}
	else if(ansMap[make_pair(h+dy[i], w+dx[i])] > tmp) {
          ansMap[pair<int,int>(w+i, h+i)] = tmp;
	  search(h+dy[i], w+dx[i], cnt+1);
	}
      }
    }
  }
  */
  for(int k=0; k<4; k++) {
    int nh = h+dy[k], nw = w+dx[k];
    if(0<=nh && nh<Height && 0<=nw && nw<Width && !Used[nh][nw] && !Pass[h][w][nh][nw]) {
      Used[nh][nw] = true;
      search(nh, nw, cnt+1);
      Used[nh][nw] = false;
    }
  }

}

int main() {
  while(1) {
    cin>>Width;
    cin>>Height;
    if(Width==0 && Height==0) {
      break;
    }
    memset(Pass,-1,sizeof(Pass));
    for(int i=0; i<Height; i++) {
      for(int j=0; j<Width-1; j++) {
        cin>>Pass[i][j][i][j+1]; // 0なら通行可
	Pass[i][j+1][i][j] = Pass[i][j][i][j+1];
      }
      if(i==Height-1)continue;
      for(int j=0; j<Width; j++) {
	cin>>Pass[i][j][i+1][j];
	Pass[i+1][j][i][j] = Pass[i][j][i+1][j];
      }
    }
    memset(Used, 0, sizeof(Used));
    Ans = 999999;
    search(0, 0, 1);

    //cout<<"Hello"<<endl;
    //cout<<ansMap[pair<int, int> (Height-1, Width-1)] <<endl;
    if(Ans == 999999)
      cout<<"0"<<endl;
    else
      cout<<Ans<<endl;
  }
}