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 <algorithm>
#include <string>
#include <queue>
 
using namespace std;

struct co{
	int x;
	int y;
	int d;
};

int mini(int p, int q){
	if( p > q ) return q;
	return p;
}

void push_q(int x, int y, vector< vector< bool > > *visited, queue< co > *q, vector< vector< bool > > *maze , int dist) {


	if( ( x < 0 ) || ( y < 0 ) )	return;
	if( y >= maze->size() )			return;
	if( x >= maze->at(y).size() )	return;
	if( maze->at(y).at(x) == true ) return;

	
	if ( visited->at(y).at(x) == false ) {
		co c;
		c.x = x;
		c.y = y;
		c.d = dist;
		visited->at(y).at(x) = true;
		q->push( c );
	}
}

//幅優先探索
int search_bfs(vector<vector<bool>> *visited, vector< vector<bool> > *maze, queue< co > *q , int w, int h){
	
	//if( x == 0 && y == 0 ) return depth;
	//x,yが範囲外の値かどうかチェック


	while( q->empty() == false ){
		co c;
		c = q->front();
		

		if( c.x == 0 && c.y == 0 ) return c.d;

		q -> pop();
		
		if( c.y % 2 == 0 ) {
			push_q(c.x + 1, c.y + 1, visited, q, maze, c.d + 1);
			push_q(c.x, c.y + 1, visited, q, maze, c.d + 1);
			push_q(c.x + 1, c.y - 1, visited, q, maze, c.d + 1);
			push_q(c.x, c.y - 1, visited, q, maze, c.d + 1);
			push_q(c.x, c.y + 2, visited, q, maze, c.d + 1);
			push_q(c.x, c.y - 2, visited, q, maze, c.d + 1);
		} else {
			push_q(c.x - 1, c.y + 1, visited, q, maze, c.d + 1);
			push_q(c.x, c.y + 1, visited, q, maze, c.d + 1);
			push_q(c.x - 1, c.y - 1, visited, q, maze, c.d + 1);
			push_q(c.x, c.y - 1, visited, q, maze, c.d + 1);
			push_q(c.x + 1, c.y, visited, q, maze, c.d + 1);
			push_q(c.x - 1, c.y, visited, q, maze, c.d + 1);
		}
	}

	return 0;
}


int main(void){
   //FILE* fp_in = freopen("data.txt", "r", stdin);
	
	while( 1 ) {
		//■■■■情報取得部分■■■■

		vector< vector< bool > > maze;
		int w, h;
		cin >> w >> h;
		if( w == 0 && h == 0 ) break;

		//最上段
		vector< bool > temp;
		for(int i = 0; i < w; i++) temp.push_back( true );
		maze.push_back( temp );

		//読み取り
		for(int i = 0; i < 2 * h - 1; i++) {
			vector< bool > newmaze;
			if( i % 2 == 0 ) {
				newmaze.push_back( true );
				for(int j = 0; j < w - 1; j++) {
					bool tmp;
					cin >> tmp;
					newmaze.push_back( tmp );
				}
				newmaze.push_back( true );
			} else {
				for(int j = 0; j < w; j++) {
					bool tmp;
					cin >> tmp;
					newmaze.push_back( tmp );
				}
			}
			maze.push_back( newmaze );
		}
	
		maze.push_back( temp );	//最下段
		maze.at( 0 ).at( 0 ) = false;
		maze.at( maze.size() - 1 ).at( maze.at( maze.size() - 1 ).size() - 1 ) = false;

		co c;
		c.y = maze.size() - 1;
		c.x = maze.at( maze.size() - 1 ).size() - 1;
		c.d = 0;
		queue< co > memo;
		memo.push( c );


		vector< vector< bool > > visited;
		for(int i = 0; i < maze.size(); i++) {
			vector< bool > visit;
			for(int j = 0; j < maze.at(i).size(); j++)
				visit.push_back(false);
			visited.push_back( visit );
		}

		visited.at(c.y).at(c.x) = true;
		

		cout << search_bfs(&visited, &maze, &memo, w, h) << endl;

	}


	//while(1){}
 
   return 0;
}