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 <utility>
#include <queue>
typedef std::pair<int, int> P;
int INF = 1e9;
int dx[4] = {-1, 0, 1, 0};
int dy[4] = {0, -1, 0, 1};
int main(){
    while(1){
        int w, h;
        std::cin >> w >> h;
        if(w == 0 && h == 0) break;
        std::vector<std::vector<int>> hori(h, std::vector<int>(w -1));
        std::vector<std::vector<int>> ver(h - 1, std::vector<int> (w));
        std::vector<std::vector<int>> d(h, std::vector<int> (w, INF));
        std::vector<std::vector<int>> used(h, std::vector<int> (w, 0));
        for(int i = 0; i < 2* h - 1; i++){
            if(i % 2 == 0){
                for(int j = 0; j < w - 1; j++) std::cin >> hori[i / 2][j];
            }
            else for(int j = 0; j < w; j++) std::cin >> ver[i / 2][j];
        }
        std::queue<P> q;
        q.push(P(0, 0));
        used[0][0] = 1;
        d[0][0] = 1;
        while(!q.empty()){
            P t = q.front();
            q.pop();
            for(int i = 0; i < 4; i++){
                int x = t.first + dx[i], y = t.second + dy[i];
                if(i == 0 && 0 <= x && x < h && 0 <= y && y < w && used[x][y] == 0){
                    if(ver[x][y] == 0){
                        d[x][y] = std::min(d[x][y], d[t.first][t.second] + 1);
                        used[x][y] = 1;
                        q.push(P(x, y));
                    }
                }
                else if(i == 1 && 0 <= x && x < h && 0 <= y && y < w && used[x][y] == 0){
                    if(hori[x][y] == 0){
                        d[x][y] = std::min(d[x][y], d[t.first][t.second] + 1);
                        used[x][y] = 1;
                        q.push(P(x, y));
                    }
                }
                else if(i == 2 && 0 <= x && x < h && 0 <= y && y < w && used[x][y] == 0){
                    if(ver[x - 1][y] == 0){
                        d[x][y] = std::min(d[x][y], d[t.first][t.second] + 1);
                        used[x][y] = 1;
                        q.push(P(x, y));
                    }
                }
                else if(i == 3 && 0 <= x && x < h && 0 <= y && y < w && used[x][y] == 0){
                    if(hori[x][y - 1] == 0){
                        d[x][y] = std::min(d[x][y], d[t.first][t.second] + 1);
                        used[x][y] = 1;
                        q.push(P(x, y));
                    }
                }
            }
        }
        if(d[h- 1][w - 1] == INF){
            std::cout << 0 << std::endl;
        }
        else std::cout << d[h - 1][w - 1] << std::endl;
    }
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define repI(i, d, n) for (int i = (d); i < (n); ++i)
#define INF 10010
#define H 30
#define W 30
using namespace std;
using ll = long long;
using P = pair<int, int>;

int m[2*H-1][2*W-1];
int cost[2*H-1][2*W-1];

int bfs(int h, int w) {
  // Map is created;
  rep(i, 2*h-1)
    rep(j, 2*w-1)
      m[i][j] = -1;

  rep(i, 2*h-1){
    rep(j, w) {
      if (i % 2 == 0 && j == 0) continue;
      if (i % 2 == 0) {
        cin >> m[i][2*j-1];
      } else {
        cin >> m[i][2*j];
      }
    }
  }

  // Cost_Table is created;
  rep(i, 2*h-1)
    rep(j, 2*w-1)
      cost[i][j] = INF;

  cost[0][0] = 1;

  queue<P> q;
  q.push(P(0, 0));

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

  while(! q.empty()) {
    int xx, yy;
    yy = q.front().first; xx = q.front().second;
    q.pop();

    rep(i, 4) {
      int ny, nx;
      ny = yy + dy[i]; nx = xx + dx[i];

      if (ny < 0 || ny >= 2*h-1 || nx < 0 || nx >= 2*w-1) continue;
      if (m[ny][nx] == 1) continue;
      if (cost[ny+dy[i]][nx+dx[i]] != INF) continue;

      q.push(P(ny+dy[i], nx+dx[i]));
      cost[ny+dy[i]][nx+dx[i]] = cost[yy][xx] + 1;

      if (ny+dy[i] == 2*h-2 && nx+dx[i] == 2*w-2) {
        return cost[ny+dy[i]][nx+dx[i]];
      }
    }
  }

  return 0;
}

int main() {
  ll w, h;
  while(cin >> w >> h) {
    if (w == 0 && h == 0) break;
    cout << bfs(h, w) << endl;
  }

  return 0;

}