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

#define INF (int)1e09

using std::cin;
using std::cout;
using std::endl;
using std::setprecision;
using std::fixed;
using std::pair;
using std::make_pair;
using std::min;
using std::max;
using std::string;
using std::vector;
using std::list;
using std::map;
using std::set; // insert erase find count
using std::queue;
using std::priority_queue;
using std::stack;

template <typename T> using Vec = vector<T>; // c++11
typedef pair<int, int> PII;
typedef pair<int, pair<int, int> > PIII;

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

struct Data {
    int dist;
    int y;
    int x;

    Data(int dist0, int y0, int x0) {
        dist = dist0;
        y = y0;
        x = x0;
    }
};

int bfs(Vec<Vec<int> >& table, int h, int w) {
    queue<Data> que;
    Data start(0, 1, 1);
    table[start.y][start.x] = 1;
    que.push(start);

    while (!que.empty()) {
        Data now = que.front();
        que.pop();
        if (now.y == 2 * h - 1 && now.x == 2 * w - 1) {
            return now.dist;
        }
        for (int i = 0; i < 4; i++) {
            if (table[now.y + dy[i]][now.x + dx[i]] != 1) {
                table[now.y + dy[i]][now.x + dx[i]] = 1;
                Data new_insert(now.dist + 1, now.y + dy[i], now.x + dx[i]);
                que.push(new_insert); 
            }
        }
    }

    return 0;
}

void dump(Vec<Vec<int> >& table) {
    for (int i = 0; i < (int)table.size(); i++) {
        for (int j = 0; j < (int)table[0].size(); j++) {
            cout << table[i][j] << " ";
        }
        cout << endl;
    }
    return;
}

int main(void) {
    while (1) {
        int w;
        int h;
        cin >> w >> h;
        if (w == 0 && h == 0) {
            break;
        }
        Vec<Vec<int> > table(2 * h + 1, Vec<int>(2 * w + 1, 0));
        for (int i = 0; i < 2 * w + 1; i++) {
            table[0][i] = 1;
            table[2 * h][i] = 1;
        }
        for (int i = 0; i < 2 * h + 1; i++) {
            table[i][0] = 1;
            table[i][2 * w] = 1;
        }
        for (int i = 0; i < h; i++) {
            for (int j = 0; j < w; j++) {
                table[2 * (i + 1)][2 * (j + 1)] = 1;
            }
        }

        for (int i = 0; i < h - 1; i++) {
            for (int j = 0; j < w - 1; j++) {
                cin >> table[2 * i + 1][2 * (j + 1)];
            }
            for (int j = 0; j <= w - 1; j++) {
                cin >> table[2 * i + 2][2 * j + 1];
            }
        }
        for (int j = 0; j < w - 1; j++) {
            cin >> table[2 * (h - 1) + 1][2 * (j + 1)];
        }
        //dump(table);
        int ans = bfs(table, h, w);
        if (ans == 0) {
            cout << 0 << endl;
        } else {
            cout << ans / 2 + 1 << endl;
        }
    }
    return 0;
}

C++: #include <iostream>
#include <vector>
#include <queue>
#include <stack>
#include <algorithm>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>

using namespace std;

typedef long long ll;
#define REP(i,b,n) for(int i=b;i<n;i++)
#define rep(i,n) REP(i,0,n)
int w,h;
char maze[200][200];
typedef pair<pair<int,int> , int > State;
int dx[]={1,0,-1,0};
int dy[]={0,1,0,-1};

void solve(){
  queue<State> q;
  pair<int,int> goal(2*w-2,2*h-2);
  q.push(State(make_pair<int,int>(0,0),1));
  while(!q.empty()){
    State cur = q.front();q.pop();
    if(goal==cur.first){
      cout<<cur.second<<endl;
      return ;
    }
    for(int i=0;i<4;i++){
      int nx=cur.first.first+dx[i];
      int ny=cur.first.second+dy[i];
      if(nx<0||ny<0||nx>goal.first||ny>goal.second||maze[ny][nx]=='1')continue;
      nx+=dx[i];
      ny+=dy[i];
      if(nx<0||ny<0||nx>goal.first||ny>goal.second||maze[ny][nx]=='1')continue;
      maze[ny][nx]='1';
      q.push(State(make_pair<int,int>(nx,ny),cur.second+1));
    }
  }
  cout<<0<<endl;
  return;
}
int main(){
  while(cin >> w >> h && (w||h)){
    for(int i=0;i<200;i++)for(int j=0;j<200;j++)maze[i][j]='0';
    for(int i=0;i<h*2-1;i++){
      if(i%2){
	for(int j=0;j<w;j++)cin>>maze[i][j*2];
      }
      else{
	for(int j=0;j<w-1;j++)cin>>maze[i][j*2+1];
      }
    }
    solve();
  }
  return 0;
}