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 <cstring>
#include <queue>

using namespace std;



int _W, _H;
int W, H;

int map[500][500];

struct state {
	int x, y, d;
	state(int _x, int _y, int _d) : x(_x), y(_y), d(_d) {}
};

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

int solver() {
	int ans = (int)1e9;
	
	int gx = W-1, gy = H-1;
	
	queue<state> q;
	q.push(state(0, 0, 1));
	
	while (!q.empty()) {
		state s = q.front(); q.pop();
		
		if (s.d >= ans) continue;
		
		if (s.x == gx && s.y == gy) {
			ans = min(ans, s.d);
			continue;
		}
		
		for (int i=0; i<4; i++) {
			if (!(0 <= s.y + dy[i] && s.y + dy[i] < H && 0 <= s.x + dx[i] && s.x + dx[i] < W)) continue;
		
			if (map[s.y + dy[i]][s.x + dx[i]] == 0) {
				map[s.y + dy[i]][s.x + dx[i]] = -1;
				map[s.y + 2 * dy[i]][s.x + 2*dx[i]] = -1;
				q.push(state(s.x + 2*dx[i], s.y + 2*dy[i], s.d + 1));
			}
		}
	}
	
	if (ans == (int)1e9) ans = 0;
	return ans;
}

int main() {
	
	while (1) {
		cin >> _W >> _H; if (_W == 0 && _H == 0) break;
		W = 2*_W - 1; H = 2*_H - 1;
		
		memset(map, 0, sizeof(map));
		cin.ignore();
		
		string str;
		for (int i=0; i<H; i++) {
			getline(cin, str);
			
			int n = (int)str.size();
			for (int j=0; j<n; j++) {
				if (str[j] == '1') {
					map[i][j] = 1;
				}
			}
		}
		
		cout << solver() << endl;
	}
	
	return 0;
}

C++: 
#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <vector>
#include <string>
#include <queue>
#include <algorithm>
#include <math.h>
#include <utility>
#include <set>
#include <map>
#include <cstring>
#include <cstdio>
#include <stack>
#define INF 1000000000
#define rep(i,n) for(int i =0;i<n;i++)
using namespace std;
typedef long long int ll;

struct tp{
    int a;
    int b;
    int c;
};

int ans =0;
queue<tp> Q;
int g[150][150];
int w,h;


int main(){
    for (;;){
        cin >> w >>h;
        if(!w and !h) break;
        memset(g, 0, sizeof(g));
        for (int i=0; i<2*h-1; i++){
            if(i%2==0){
                for (int j=1; j<2*w-1; j+=2) {
                    int p;
                    cin >> p;
                    if(p ==1) g[i][j] = 1;
                }
            }else{
                for (int j=0; j<2*w-1; j+=2) {
                    int p;
                    cin >> p;
                    if(p ==1) g[i][j] = 1;
                }
            }
        }
        Q.push({0,0,1});
        int ch = 0;
        int used[100][100];
        used[0][0]=1;
        memset(used,0, sizeof(used));
        while(!Q.empty()){
            int x = Q.front().a;
            int y = Q.front().b;
            int num = Q.front().c;
            Q.pop();
            if(x == h*2-1-1 and y == 2*w-1-1 ){
                ch = 1;
                ans = num;
                break;
            }
            used[x][y]=1;
            if (y+2 < 2*w-1 and g[x][y+1]!=1 and used[x][y+2]==0) {
                Q.push({x,y+2,num+1});
            }
            if (y-2>=0 and g[x][y-1]!=1 and used[x][y-2]==0) {
                Q.push({x,y-2,num+1});
            }
            if (x+2<2*h-1 and g[x+1][y]!=1 and used[x+2][y]==0) {
                Q.push({x+2,y,num+ 1});
            }
            if (y-2>=0 and g[x-1][y]!=1 and used[x-2][y]==0) {
                Q.push({x-2,y,num+1});
            }
        }
        if(ch == 1){
            cout << ans <<endl;
        }else{
            cout << 0 << endl;
        }
    }
}