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 <bits/stdc++.h>

using namespace std;
using ll =long long;
#define SORT(a) sort((a).begin(),(a).end())
#define rSORT(a) reverse((a).begin(),(a).end())
#define For(i, a, b) for(int i = (a) ; i < (b) ; ++i)
#define rep(i, n) For(i, 0, n)
#define debug(x) cerr << #x << " = " << (x) << endl;
#define P pair<int,int>
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
void coY() {cout <<"Yes"<<endl;}
void coN(){cout <<"No"<<endl;}
const int INF = 100100100;
const int mod = 1e9+7;
const int dx[4] = {1,0,-1,0};
const int dy[4] = {0,1,0,-1};
//Write From this Line

int main()
{
	//fiel[i][j] = pair(true,false)みたいな…
	while(1){
		int w , h ;
		cin >> w >> h ;
		if(w == 0 && h == 0) break;
		vector<vector<P>> field(h,vector<P> (w));
		rep(i,2*h-1){
			// i / 2行目について、
			if(i % 2 == 0){
				//縦線
				rep(j,w-1){
					cin >> field[i/2][j].second;
				}
			} else {
				//上と下をつなぐところ
				rep(j,w){
					cin >> field[i/2][j].first;
				}
			}
		}
		//fieldが出来たので、h-1,w-1に行くまでの手数を数える
		vector<vector<int>> dist(h,vector<int>(w));
		rep(i,h)rep(j,w) dist[i][j] = INF ;
		queue<P> que;
		auto update = [&](int i, int j, int x){
			if(dist[i][j] != INF) return ;
			dist[i][j] = x;
			que.push(make_pair(i,j));
		};
		update(0,0,1);
		while(!que.empty()){
			int y = que.front().first;
			int x = que.front().second;
			que.pop();
			rep(dir,4){
				int ny = y + dy[dir];
				int nx = x + dx[dir];
				if(ny < 0 || ny >= h || nx < 0 || nx >= w) continue;
				if(dist[ny][nx] != INF) continue;
				//TODO　移動出来ないときの処理を書く。
				//とりあえず、上から下、左から右に行くと仮定して処理を書く
				//i = 0のとき右に行く
				if(dir==0){
					//右に行けるかどうか/secondを見る
					if(field[y][x].second) continue;
				}
				if(dir == 1){
					//下に行けるかどうか
					if(field[y][x].first) continue;
				}
				if(dir == 2){
					//ひだりにイケるかどうか
					if(field[ny][nx].second) continue;
				}
				if( dir == 3){
					//上に行けるか
					if(field[ny][nx].first) continue;
				}
				update(ny,nx,dist[y][x]+1);
			}
		}
		if(dist[h-1][w-1] == INF){
			cout << 0 << endl;
		}else {
			cout << dist[h-1][w-1] << endl;
		}
	}
}

C++: #include <vector>
#include <list>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <deque>
#include <algorithm>
#include <utility>
#include <functional>
#include <sstream>
#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <climits>
#include <cassert>
using namespace std;
inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<string> vs;
typedef pair<int, int> pii;
typedef long long ll;
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
const double EPS = 1e-10;
const double PI  = acos(-1.0);

int dx[]={-1,0,1,0},dy[]={0,-1,0,1};
int main(){
	int w,h;
	while(cin>>w>>h,w|h){
		vvi ver(h,vi(w-1));
		vvi hor(h-1,vi(w));
		REP(i,h){
			REP(j,w-1){
				cin>>ver[i][j];
			}
			if(i<h-1){
				REP(j,w){
					cin>>hor[i][j];
				}
			}
		}
		queue<pii> q;
		vvi cost(h,vi(w));
		q.push(make_pair(0,0));
		cost[0][0]=1;
		while(!q.empty()){
			pii p=q.front();q.pop();
			REP(d,4){
				int y=p.first+dy[d];
				int x=p.second+dx[d];
				if(y>=0&&x>=0&&y<h&&x<w&&!cost[y][x]){
					bool ok=false;
					switch(d){
					case 0:
						ok=!ver[y][x];break;
					case 2:
						ok=!ver[y][x-1];break;
					case 1:
						ok=!hor[y][x];break;
					case 3:
						ok=!hor[y-1][x];break;
					}
					if(ok){
						q.push(make_pair(y,x));
						cost[y][x]=cost[p.first][p.second]+1;
					}
				}
			}
		}
		cout<<cost[h-1][w-1]<<endl;
	}
}