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 <bits/stdc++.h>
#define rep(i, n) for (int i=0; i<(n); ++i)
#define repr(i, a, b) for (int i=a; i<(b); ++i)
#define reprev(i, n) for (int i=n-1; i>=0; --i)
#define reprrev(i, a, b) for (int i=b-1; i>=(a); --i)
using namespace std;
using ll = long long;
using P = pair<int, int>;

int main() {
    cout << fixed << setprecision(10);

    int w, h; cin >> w >> h;
    
    while (w != 0 && h != 0) {
        vector<vector<int>> hrzd(h, vector<int>(w-1)), vtcd(h-1, vector<int>(w));
        rep(i, h*2-1) {
            if (i % 2 == 0) {
                rep(j, w-1) cin >> hrzd[i/2][j];
                // cout << "hrzd; " << i << endl; 
            } else {
                rep(j, w) cin >> vtcd[i/2][j];
                // cout << "vtcd; " << i << endl;
            }
        }
        queue<P> q;
        q.emplace(make_pair(0, 0));
        vector<vector<int>> dl(h, vector<int>(w));
        dl[0][0] = 1;

        while(!q.empty()) {
            P pp = q.front(); q.pop();
            int nh, nw;
            // 横方向の移動
            // 右に動く場合
            nh = pp.first, nw = pp.second + 1;
            if (nh >= 0 && nw >= 0 && nh < h && nw < w && hrzd[nh][nw-1] == 0 && dl[nh][nw] == 0) {
                q.emplace(make_pair(nh, nw));
                dl[nh][nw] = dl[pp.first][pp.second] + 1;
            }

            // 左に動く場合
            nh = pp.first, nw = pp.second - 1;
            if (nh >= 0 && nw >= 0 && nh < h && nw < w && hrzd[nh][nw] == 0 && dl[nh][nw] == 0) {
                q.emplace(make_pair(nh, nw));
                dl[nh][nw] = dl[pp.first][pp.second] + 1;
            }

            // 上に動く場合
            nh = pp.first - 1, nw = pp.second;
            if (nh >= 0 && nw >= 0 && nh < h && nw < w && vtcd[nh][nw] == 0 && dl[nh][nw] == 0) {
                q.emplace(make_pair(nh, nw));
                dl[nh][nw] = dl[pp.first][pp.second] + 1;
            }

            // 下に動く場合
            nh = pp.first + 1, nw = pp.second;
            if (nh >= 0 && nw >= 0 && nh < h && nw < w && vtcd[nh-1][nw] == 0 && dl[nh][nw] == 0) {
                q.emplace(make_pair(nh, nw));
                dl[nh][nw] = dl[pp.first][pp.second] + 1;
            }
        }
        cout << dl[h-1][w-1] << endl;

        cin >> w >> h;
    }
    return 0;
}