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<queue>
#include<vector>
using namespace std;

class Input {
public:
	int w, h;
	int data;
	vector<int> et[10000];	//i???j???????????????i*w + j??§??¨???
	
	bool input() {
		cin >> w >> h;
		if (!w) {
			return false;
		}
		
		for (int i = 0; i < 2 * h -1; i++) {
			for (int j = 0; j < w - (i%2==0); j++) {
				cin >> data;
				if (data != 0) {
					continue;
				}
				if (i%2 == 0) {
					et[i/2*w + j].push_back(i/2*w + j + 1);
					et[i/2*w + j + 1].push_back(i/2*w + j);
				}
				else {
					et[i/2*w + j].push_back(i/2*w + w + j);
					et[i/2*w + w + j].push_back(i/2*w + j);
				}
			}
		}
		return true;
	}
	void clear() {
		for (int i = 0; i < (w+1)*(h+1); i++) {
			et[i].clear();
		}
	}
};

class Solver : public Input {
public:
	int bfs(int st, int ed) {
		typedef pair<int, int> P;
		queue<P> que;
		int mincost[10000], INF = 100000;
		for (int i = 0; i < h * w; i++) {
			mincost[i] = INF;
		}
		
		que.push(P(0, st) );
		while(!que.empty() ) {
			P now = que.front();
			que.pop();
			int sc = now.first;
			int v = now.second;
			
			if (mincost[v] <= sc)
				continue;
			mincost[v] = sc;
			
			for (int i = 0; i < et[v].size(); i++) {
				if (mincost[et[v][i]] > sc + 1) {
					que.push(P(sc + 1, et[v][i]) );
				}
			}
		}
		
		/*for (int i = 0; i < h*w; i++) {
			cout << "mincost[" << i << "] = " << mincost[i ]<< endl;
		}*/
		return mincost[ed];
	}
	int solve() {
		int res = bfs(0, h*w-1);
		if (res >= 100000) {
			return 0;
		}
		return res + 1;
	}
}solver;

signed main() {
	while (solver.input() ) {
		int res = solver.solve();
		cout << res << endl;
		solver.clear();
	}
	return 0;
}

C++: #include<iostream>
#include<iomanip>
#include<cstdlib>
#include<stdio.h>
#include<time.h>
#include<math.h>
#include<algorithm>
#include<string>
#include<vector>
#include<list>
#include<queue>
#include<stack>
#include<deque>
#include<set>
#include<map>
#define REP(i, N) for(ll i = 0; i < N; ++i)
#define FOR(i, a, b) for(ll i = a; i < b; ++i)
#define ALL(a) (a).begin(),(a).end()
#define pb push_back
#define INF 1000000000
#define MOD 1000000007
using namespace std;
typedef long long ll;
typedef pair<ll, ll> P;
int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};
int qx[8] = {1, 1, 0, -1, -1, -1, 0, 1};
int qy[8] = {0, 1, 1, 1, 0, -1, -1, -1};

int main(void) {
	while(true) {
		int w, h;
		cin>>w>>h;
		if(w == 0 && h == 0) break;
		vector<vector<int> > d(h, vector<int>(w, INF));
		vector<vector<int> > m(2 * h - 1, vector<int>(w));
		REP(i, 2 * h - 1) {
			if(i % 2 == 0) {
				REP(j, w - 1) {
					cin>>m[i][j];
				}
			} else {
				REP(j, w) {
					cin>>m[i][j];
				}
			}
		}
		d[0][0] = 0;
		queue<P> q;
		q.push(P(0, 0));
		while(!q.empty()) {
			P p = q.front();
			q.pop();
			REP(i, 4) {
				ll nh = p.first + dx[i];
				ll nw = p.second + dy[i];
				if(nh >= 0 && nh < h && nw >= 0 && nw < w && d[nh][nw] == INF) {
					switch(i) {
						case 0: {
							if(m[2 * p.first + 1][p.second] == 0) {
								d[nh][nw] = d[p.first][p.second] + 1;
								q.push(P(nh, nw));
							}
							break;
						}
						case 1: {
							if(m[2 * p.first][p.second] == 0) {
								d[nh][nw] = d[p.first][p.second] + 1;
								q.push(P(nh, nw));
							}
							break;
						}
						case 2: {
							if(m[2 * (p.first - 1) + 1][p.second] == 0) {
								d[nh][nw] = d[p.first][p.second] + 1;
								q.push(P(nh, nw));
							}
							break;
						}
						case 3: {
							if(m[2 * p.first][p.second - 1] == 0) {
								d[nh][nw] = d[p.first][p.second] + 1;
								q.push(P(nh, nw));
							}
							break;
						}
					}
				}
			}
		}
		if(d[h - 1][w - 1] == INF) cout<<0<<endl;
		else cout<<d[h - 1][w - 1] + 1<<endl;
	}
}