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 <algorithm>
#include <iostream>
#include <limits.h>
#include <math.h>
#include <set>
#include <stack>
#include <stdlib.h>
#include <string>
#include <vector>

#define el endl
#define fd fixed
#define INF INT_MAX/2-1
#define pb push_back

using namespace std;

void visit(int x, int y, int w, int h, int **hor, int **ver, int **memo) {
  if (x == w-1 && y == h-1) return;
  if (x > 0 && ver[y][x] == 0 && memo[y][x] +1 < memo[y][x-1]) {
    memo[y][x-1] = memo[y][x] + 1;
    visit(x-1, y, w, h, hor, ver, memo);
  }
  if (y > 0 && hor[y][x] == 0 && memo[y][x] +1 < memo[y-1][x]) {
    memo[y-1][x] = memo[y][x] + 1;
    visit(x, y-1, w, h, hor, ver, memo);
  }
  if (x < w-1 && ver[y][x+1] == 0 && memo[y][x] +1 < memo[y][x+1]) {
    memo[y][x+1] = memo[y][x] + 1;
    visit(x+1, y, w, h, hor, ver, memo);
  }
  if (y < h-1 && hor[y+1][x] == 0 && memo[y][x] +1 < memo[y+1][x]) {
    memo[y+1][x] = memo[y][x] + 1;
    visit(x, y+1, w, h, hor, ver, memo);
  }
}

int main() {
  int w, h, tmp;
  while (cin >> w >> h, w | h) {
    int hor[h+1][w], ver[h][w+1], memo[h][w];
    //initialize
    for (int i = 0; i < h+1; i++) {
      for (int j = 0; j < w; j++) {
        hor[i][j] = 1;
      }
    }
    for (int i = 0; i < h; i++) {
      for (int j = 0; j < w+1; j++) {
        ver[i][j] = 1;
      }
    }
    for (int i = 0; i < h; i++) {
      for (int j = 0; j < w; j++) {
        memo[i][j] = INF;
      }
    }
    memo[0][0] = 1;
    //input
    for (int i = 0; i < 2*h-1; i++) {
      if (i & 1) {
        for (int j = 0; j < w; j++) {
          cin >> tmp;
          hor[i/2+1][j] = tmp;
        }
      } else {
        for (int j = 0; j < w-1; j++) {
          cin >> tmp;
          ver[i/2][j+1] = tmp;
        }
      }
    }
    int *hor_tmp[h+1], *ver_tmp[h], *memo_tmp[h];
    for (int i = 0; i < h; i++) {
      hor_tmp[i] = hor[i];
      ver_tmp[i] = ver[i];
      memo_tmp[i] = memo[i];
    }
    hor_tmp[h] = hor[h];
    visit(0, 0, w, h, hor_tmp, ver_tmp, memo_tmp);
    if (memo[h-1][w-1] == INF) cout << "0" << el;
    else cout << memo[h-1][w-1] << el;
  }
}

C++: #include <cstdio>
#include <iostream>
#include <bits/stdc++.h>

using namespace std;

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

typedef long long ll;
int dx[]={-1,0,1,0};
int dy[]={0,1,0,-1};

struct aa{
    int x;
    int y;
    int cost;
};
int main()
{
    while(true){
        int W,H;cin>>W>>H;
        if(!W)break;
        vector<vector<vector<int>>>walls(H,vector<vector<int>>(W,vector<int>(4,1)));
        for(int y=0;y<2*H-1;++y){
            if(y%2){
                //テヲツィツェテァツキツ?   
                for(int x=0;x<W;++x){
                    int a;cin>>a;
                    if(!a){
                        walls[y/2][x][1]=false;
                        walls[y/2+1][x][3]=false;
                    }
                }
            }else{
                //テァツクツヲテァツキツ?
                for(int x=0;x<W-1;++x){
                    int a;cin>>a;
                    if(!a){
                        walls[y/2][x+1][0]=false;
                        walls[y/2][x][2]=false;
                    }
                }
            }
        }
        queue<aa>que;
        vector<vector<int>>memo(H,vector<int>(W,100000));
        memo[0][0]=0;
        que.push(aa{0,0,0});
        while(!que.empty()){
            aa atop(que.front());
            que.pop();
            for(int way=0;way<4;++way){
                if(!walls[atop.y][atop.x][way]){
                    int nextx=atop.x+dx[way];
                    int nexty=atop.y+dy[way];
                    int nextcost=atop.cost+1;
                    if(nextx>=0&&nextx<W&&nexty>=0&&nexty<H){
                        if(memo[nexty][nextx]>nextcost){
                            memo[nexty][nextx]=nextcost;
                            que.push(aa{nextx,nexty,nextcost});
                        }
                    }
                }
            }
        }
        int ans=memo[H-1][W-1];
        if(ans>10000){
            ans=0;
        }else{
            ans++;
        }
        cout<<ans<<endl;

        //bfs

    }
    
    return 0;
}