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 <algorithm>
#include <bitset>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>

#define rep(i,a) for(int i = 0;i < (a); i++)
#define repi(i,a,b) for(int i = (a); i < (b); i++)
#define repd(i,a,b) for(int i = (a); i >= (b); i--)
#define repit(i,a) for(__typeof((a).begin()) i = (a).begin(); i != (a).end(); i++)
#define all(u) (u).begin(),(u).end()
#define rall(u) (u).rbegin(),(u).rend()
#define UNIQUE(u) (u).erase(unique(all(u)),(u).end())
#define pb push_back
#define mp make_pair
#define INF 1e9
#define EPS 1e-9
#define PI acos(-1.0)

using namespace std;

typedef long long ll;
typedef vector<int> vi;
int w, h;
int dx[] = {-1, 0, 1, 0};
int dy[] = {0, -1, 0, 1};
bool inrange(int y, int x){
    return y >= 0 && x >= 0 && x < w && y < h;
}
int wall[31][31][31][31];
struct node{
    int y;
    int x;
    int cst;
    bool operator<(const node &o)const{
        return cst > o.cst;
    }
};
int main() {
    while(cin >> w >> h, w){
        int tmp;
        memset(wall, 0, sizeof(wall));
        rep(i, h){
            rep(j, w-1){
                cin >> tmp;
                wall[i][j][i][j+1] = tmp;
                wall[i][j+1][i][j] = tmp;
            }
            if(i != h-1) {
                rep(j, w){
                    cin >> tmp;
                    wall[i][j][i+1][j] = tmp;
                    wall[i+1][j][i][j] = tmp;
                }
            }
        }
        int ans = 0;
        int done[31][31] = {0};
        priority_queue<node> pq;
        pq.push((node){0,0,1});
        while(!pq.empty()){
            int y = pq.top().y;
            int x = pq.top().x;
            int cst = pq.top().cst;
            pq.pop();
//            cout << x << " " << y << "  "<< cst << endl;
            if(x == w-1 && y == h-1){
                ans = cst;
                break;
            }
            if(done[y][x]) continue;
            done[y][x] = 1;
            rep(i, 4){
                int ny = y + dy[i];
                int nx = x + dx[i];
                if(inrange(ny, nx) && !wall[y][x][ny][nx]) pq.push((node){ny, nx, cst + 1});
            }
        }
        cout << ans << endl;
    }
    return 0;
}

C++: #include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <queue>
#include <stdio.h>
using namespace std;
#define rep(i,n) for (int i=0; i < (int)(n); i++)
//typedef long long ll;

int dist[30][30];
const int inf = 100000;
struct Point {
	int x, y, count;
};
int dx[] = {0,1,0,-1};
int dy[] = {-1,0,1,0};

int main() {
	int w, h;
	while(true) {
		cin >> w >> h;
		if (w == 0 && h == 0) break;
		
		int virt[30][30];
		int horiz[30][30];
		
		for(int i = 0; i < h; i++) {
			for(int j = 0; j < w; j++) {
				dist[i][j] = inf;
			}
		}
		for(int i = 0; i < h; i++) {
			if (i != 0) {
				for(int j = 0; j < w; j++) {
					cin >> horiz[i-1][j];
				}
			}
			for(int j = 0; j < w - 1; j++) {
				cin >> virt[i][j];
			}
		}
		
		queue<Point> que;
		Point start;
		start.x = start.y = 0;
		start.count = 1;
		que.push(start);
		
		while(!que.empty()) {
			Point p = que.front();
			que.pop();
			
			dist[p.y][p.x] = p.count;
			
			for(int i = 0; i < 4; i++) {
				Point next;
				next.x = p.x+dx[i];
				next.y = p.y+dy[i];
				next.count = p.count + 1;
				if (next.x < 0 || w<=next.x || next.y < 0 || h <=next.y) continue;
				if (dist[next.y][next.x] != inf) continue;
				
				bool hasWall = false;
				if (dx[i] > 0) {
					hasWall = virt[p.y][p.x];
				}
				else if (dx[i] < 0) {
					hasWall = virt[p.y][p.x - 1];
				}
				else if (dy[i] > 0) {
					hasWall = horiz[p.y][p.x];
				}
				else {
					hasWall = virt[p.y - 1][p.x];
				}
				if (hasWall) {//cout <<"fff" <<p.x<<","<<p.y<<","<<i<<endl;
				continue;}
				
				que.push(next);
			}
		}
		cout << (dist[h-1][w-1] == inf ? 0: dist[h-1][w-1]) << endl;
		
	}
    return 0;
}