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 <cstdio>
#include <cstdlib>
#include <cmath>
#include <iostream>
#include <sstream>
#include <vector>
#include <string>
#include <queue>
#include <set>
#include <map>
#include <utility>
#include <algorithm>
#include <functional>

using namespace std;

#define rep(i,n) for((i)=0;(i)<(int)(n);(i)++)
#define foreach(itr,c) for(__typeof((c).begin()) itr=(c).begin();itr!=(c).end();itr++)
template<class T> void pp(T a, T b){ for(T i = a; i != b; ++i) cout << *i << ' '; cout << endl; }

struct State {
  int x,y,d;
};

int W,H;
int mp[40][40][4];
const int dx[] = {-1,0,1,0}, dy[] = {0,1,0,-1};

int bfs(void){
  int i;
  queue<State> q;
  State st; st.x = 0, st.y = 0, st.d = 1;

  q.push(st);
  while(!q.empty()){
    State now = q.front(); q.pop();
    if(now.y == H-1 && now.x == W-1) return now.d;
    //    cout << now.y << ' ' << now.x << endl;
    rep(i,4){
      if(mp[now.y][now.x][i] == 0){
        mp[now.y][now.x][i] = -1;
        int yy = now.y + dy[i];
        int xx = now.x + dx[i];
        State next; next.y = yy; next.x = xx; next.d = now.d + 1;
        q.push(next);
      }
    }
  }

  return 0;
}

int main(){
  int i,j,k;

  while(1){
    scanf("%d %d",&W,&H);
    if(W == 0 && H == 0) break;

    rep(i,40) rep(j,40) rep(k,4) mp[i][j][k] = -1;

    int d;
    rep(i,2*H-1){
      if(i%2 == 0){
        rep(j,W-1){
          scanf("%d",&d);
          if(d == 0){
            mp[i/2][j][2] = 0;
            mp[i/2][j+1][0] = 0;
          }
        }
      } else {
        rep(j,W){
          scanf("%d",&d);
          if(d == 0){
            mp[i/2][j][1] = 0;
            mp[(i/2) + 1][j][3] = 0;
          }
        }
      }
    }

    // mp[H][W][1] = 0;
    // rep(i,H) rep(j,W){ rep(k,4){ cout << mp[i][j][k] << endl; } cout << endl; }
    // cout << "check " << endl;
    
    cout << bfs() << endl;
  }

  return 0;
}

C++: #include<iostream>
using namespace std;

int field[150][150];
int dx[4] = {2, 0, -2, 0};
int dy[4] = {0, 2, 0, -2};
int ans;
int n, m;

void dfs(int x, int y, int count){
	if(0 <= x && x < m*2-1 && 0 <= y && y < n*2-1 && field[x][y] == 0){
		count++;
		field[x][y] = 1;
		if(m*2-2 == x && n*2-2 == y){
			if(count < ans) ans = count;
			return;
		}
		for(int i=0; i < 4; i++){
			if(field[x+dx[i]/2][y+dy[i]/2] == 0) dfs(x+dx[i], y+dy[i], count);
		}
		count--;
	}
}

int main(){
	int state;
	while(cin >> n >> m, n || m){
		ans = 1000000;
		for(int i=0; i < 150; i++){
			for(int j=0; j < 150; j++){
				//if(i < m*2+1 && j < n*2+1)field[i][j] = 0;
				//else field[i][j] = 1;
				field[i][j] = 0;
			}
		}
		for(int i=0; i < m*2-1; i++){
			for(int j=0; j < n; j++){
				if(i % 2 == 0 && j == n-1) break;
				cin >> state;
				if(i % 2 == 0)field[i][j*2+1] = state;
				else if(i % 2 == 1) field[i][j*2] = state;
			}
		}
		/*
		cout << endl;
		cout << n << " " << m << endl;
		for(int i=0; i < m*2-1; i++){
			for(int j=0; j < n*2-1; j++){
				cout << field[i][j];
			}
			cout << endl;
		}
		*/

		dfs(0, 0, 0);

		if(ans == 1000000) cout << 0 << endl;
		else cout << ans << endl;
	}

}