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 <vector>
#include <string>
#include <algorithm>
#include <cstring>
#include <map>
#include <queue>
#include <stack>
#include <set>
#include <functional>
#include <sstream>
#include <complex>
#include <climits>
using namespace std;

#define REP(i,a,n) for(int i=(a);i<(int)(n);i++)
#define rep(i,n) REP(i,0,n)
#define pb push_back
#define mp make_pair
#define all(x) x.begin(),x.end()
#define EPS 1e-8

class cell{
public:
	int dir[4]; // up,right,down,left;
};

int main(){
	cell field[32][32];
	const int dx[] = {0,1,0,-1};
	const int dy[] = {-1,0,1,0};
	int check[32][32];
	int w,h,s;
	while(scanf("%d%d",&w,&h),w|h){
		rep(i,32)rep(j,32)check[i][j]=INT_MAX;
		rep(i,2*h-1){
			if( i%2==0 ){	 // tatesen
				rep(j,w-1){
					scanf("%d",&s);
					field[i/2][j].dir[1] = field[i/2][j+1].dir[3] = s;
				}
			}else{ // yokosen
				rep(j,w){
					scanf("%d",&s);
					field[i/2][j].dir[2] = field[i/2+1][j].dir[0] = s;
				}
			}
		}
		/*
		rep(i,h){
			rep(j,w){
				printf("(%d,%d) u:%d, r:%d, d:%d, l:%d\n",j,i,field[i][j].dir[0],field[i][j].dir[1],field[i][j].dir[2],field[i][j].dir[3]);
			}
		}
		*/
		
		
		queue<pair<int,int> > q;
		q.push(mp(0,0));
		check[0][0] = 0;
		bool goal = false;
		while(!q.empty()){
			int x = q.front().first;
			int y = q.front().second;
			int c = check[y][x];
			q.pop();
			rep(k,4){
				int tx = x + dx[k];
				int ty = y + dy[k];
				//printf("(%d,%d) c:%d\n",tx,ty,c);
				if( tx<0 || ty<0 || tx>=w || ty>=h || check[ty][tx]<=c ) continue;
				if( field[y][x].dir[k]==1 ) continue;
				check[ty][tx] = c+1;
				//printf("(%d,%d) --> dir:%d --> (%d,%d)\n",x,y,k,tx,ty);
				if( tx==w-1 && ty==h-1 ){
					goal = true; break;
				}
				q.push(mp(tx,ty));
			}
			if( goal ) break;
		}
		printf("%d\n",check[h-1][w-1]==INT_MAX?0:check[h-1][w-1]+1);
	}
	return 0;
}

C++: #include <stdio.h>

// queue begin

#define QUEUE_SIZE 100000

typedef struct _point {
  int x, y;
} point;

point que[QUEUE_SIZE];
int head, tail;

void init() {
  head = tail = 0;
}

void push(point elm) {
  que[tail] = elm;
  tail = (tail+1) % QUEUE_SIZE;
}

point pop() {
  point elm = que[head];
  head = (head+1) % QUEUE_SIZE;
  return elm;
}

int empty() {
  return head == tail;
}

// queue end

#define MAXH 31
#define MAXW 31
#define INF (1<<28)

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

// G[y][x][d]: テ、ツスツ催ァツスツョ(x,y)テ」ツ?凝」ツつ嘉ヲツ鳴ケテ・ツ青租テ」ツ?ォテァツァツサテ・ツ仰陛」ツ?古・ツ渉ッティツδステ」ツ?凝」ツ?ゥテ」ツ??」ツ??
int G[MAXH][MAXW][4];
int cost[MAXH][MAXW];

int bfs(int sx, int sy, int gx, int gy) {
  int i, j;
  point p = {sx, sy};
  point np;

  if(sx == gx && sy == gy) return 0;

  for(i = 0; i < H; ++i) {
    for(j = 0; j < W; ++j) {
      cost[i][j] = INF;
    }
  }
  cost[sy][sx] = 0;
  init();
  push(p);
  while(!empty()) {
    p = pop();
    for(i = 0; i < 4; ++i) {
      if(G[p.y][p.x][i]) {
        np.x = p.x + dx[i];
        np.y = p.y + dy[i];
        if(cost[np.y][np.x] == INF) {
          push(np);
          cost[np.y][np.x] = cost[p.y][p.x] + 1;
          if(np.x == gx && np.y == gy) {
            return cost[np.y][np.x];
          }
        }
      }
    }
  }
  return INF;
}

int main() {
  int i, j, k, a, ans;
  while(scanf("%d %d", &W, &H) != EOF) {
    if(W == 0 && H == 0) break;
    for(i = 0; i < H; ++i) {
      for(j = 0; j < W; ++j) {
        for(k = 0; k < 4; ++k) {
          G[i][j][k] = 0;
        }
      }
    }
    for(i = 0; i < H*2-1; ++i) {
      if(i % 2 == 0) {
        for(j = 0; j < W-1; ++j) {
          scanf("%d", &a);
          if(a == 0) {
            G[i/2][j][0] = G[i/2][j+1][2] = 1;
          }
        }
      } else {
        for(j = 0; j < W; ++j) {
          scanf("%d", &a);
          if(a == 0) {
            G[i/2][j][1] = G[i/2+1][j][3] = 1;
          }
        }
      }
    }
    ans = bfs(0,0,W-1,H-1);
    if(ans == INF) ans = 0;
    else ++ans;
    printf("%d\n", ans);
  }
  return 0;
}