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 <cstdio>
#include <vector>
#include <algorithm>
#include <cmath>
#include <queue>

using namespace std;

typedef pair<int, int> P;

int main(){
	
	int w, h;
	
	while(true){
		cin >> w >> h;
		if(w * h == 0){
			break;
		}
		int map[80][80] = {};
		
		for(int i = 0; i < h * 2 - 1; i++){
			if(i % 2 == 0){
				for(int j = 1; j < w * 2 - 1; j += 2){
					cin >> map[j][i];
				}
			}else{
				for(int j = 0; j < w * 2 - 1; j += 2){
					cin >> map[j][i];
				}
			}
		}
		
		queue<P> que;
		
		P hoge;
		hoge.first = 0;
		hoge.second = 0;
		
		que.push(hoge);
		
		for(int loop = 1; loop < 1000; loop++){
			int N = que.size();
			if(N == 0){
				break;
			}
			for(int i = 0; i < N; i++){
				P p = que.front();
				que.pop();
				int x = p.first;
				int y = p.second;
				
				if(x < 0 || x >= w * 2 || y < 0 || y >= h * 2){
					continue;
				}
				if(map[x][y] != 0){
					continue;
				}
				
				map[x][y] = loop;
				
				if(x > 0 && !map[x - 1][y]){
					P p1;
					p1.first = x - 2;
					p1.second = y;
					que.push(p1);
				}
				if(y > 0 && !map[x][y - 1]){
					P p1;
					p1.first = x;
					p1.second = y - 2;
					que.push(p1);
				}
				if(!map[x + 1][y]){
					P p1;
					p1.first = x + 2;
					p1.second = y;
					que.push(p1);
				}
				if(!map[x][y + 1]){
					P p1;
					p1.first = x;
					p1.second = y + 2;
					que.push(p1);
				}
			}
		}
		/*
		for(int i = 0; i <= w * 2; i++){
			for(int j = 0; j <= h * 2; j++){
				cout << map[i][j] << " ";
			}
			cout << endl;
		}
		*/
		cout << map[w * 2 - 2][h * 2 - 2] << endl;
	}
	
	return 0;
}

C++: #include <iostream>
#include <vector>
#include <queue>
#include <utility>
#include <algorithm>

using namespace std;

#define REP(i, n) for(int i = 0; i < int(n); ++i)
#define FOR(i, a, b) for(int i = int(a); i < int(b); ++i)
#define IN(a, x, b) (a <= x && x < b)

constexpr int INFINT = 1 << 30;

int dy4[] = { -1,0,1,0 };
int dx4[] = { 0,1,0,-1 };

signed main() {
	while (true) {
		int w, h;
		cin >> w >> h;
		if (h == 0 && w == 0) break;

		vector<vector<int>> a(h - 1, vector<int>(w)), b(h, vector<int>(w - 1));
		{
			int p = 0, q = 0;
			bool isP = true;
			while (p < h || q < h - 1) {
				if (isP) {
					REP(j, w - 1) cin >> b[p][j];
					++p;
				}
				else {
					REP(j, w) cin >> a[q][j];
					++q;
				}
				isP = !isP;
			}
		}

		vector<vector<int>> dist(h, vector<int>(w, INFINT));
		dist[0][0] = 1;

		using P = pair<int, int>;
		queue<P> que({P(0, 0)});
		while (!que.empty()) {
			P now = que.front(); que.pop();
			REP(d, 4) {
				int dy = now.first + dy4[d];
				int dx = now.second + dx4[d];
				if (!IN(0, dy, h) || !IN(0, dx, w)) continue;

				if (dy4[d] == 0) {
					int mi = min(now.second, dx);
					if (b[dy][mi]) continue;
				}
				else {
					int mi = min(now.first, dy);
					if (a[mi][dx]) continue;
				}

				if (dist[dy][dx] > dist[now.first][now.second] + 1) {
					dist[dy][dx] = dist[now.first][now.second] + 1;
					que.push(P(dy, dx));
				}
			}
		}

		int ans = 0;
		if (dist[h - 1][w - 1] != INFINT) ans = dist[h - 1][w - 1];
		cout << ans << endl;
	}
}