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 <queue>
using namespace std;

struct pos{
    int x;
    int y;
    int dis;
};

int main(){
    int w, h;
    while(cin >> w >> h, w != 0 && h != 0){
        int map[65][65];
        for(int i = 0; i < 65; i++){
            for(int j = 0; j < 65; j++){
                map[j][i] = 1;
            }
        }

        for(int i = 1; i <= h; i++){
            for(int j = 1; j <= w; j++){
                map[i*2-1][j*2-1] = 0;
            }
        }

        int l = 1;
        for(int i = 1; i <= h*2-1; i++){
            if(i % 2 == 1){
                for(int j = 1; j <= w-1; j++){
                    int input;
                    cin >> input;
                    map[l*2-1][j*2] = input;
                }
            }else{
                for(int j = 1; j <= w; j++){
                    int input;
                    cin >> input;
                    map[l*2][j*2-1] = input;
                }
                l++;
            }
        }

        queue<pos> q;
        map[1][1] = 1;
        pos p;
        p.x = 1;
        p.y = 1;
        p.dis = 1;
        q.push(p);
        int x1[] = {-1, 0, 1, 0}, y1[] = {0, -1, 0, 1};
        while(!q.empty()){
            p = q.front();
            q.pop();
            for(int i = 0; i < 4; i++){
                pos p1 = p;
                p1.x += x1[i]; p1.y += y1[i];
                if(!map[p1.x][p1.y]){
                    //p1.x += x1[i]; p1.y += y1[i];
                    p1.dis++;
                    map[p1.x][p1.y] = p1.dis;
                    q.push(p1);
                }
            }
        }

        int ans = (map[h*2-1][w*2-1] + 1) /2;

        cout << ans << endl;

    }
}

C++: #include <bits/stdc++.h>
//#define int long long
#define double long double
#define rep(i, a, n) for(int i = (int)(a);(i) < (int)(n);++(i))
#define repe(i, a, n) for(int i = (int)(a);(i) <= (int)(n);++(i))
#define repif(i, a, x) for(int i = (int)(a);(x);++(i))
#define repr(i, a, n) for(int i = ((int)(a)-1);(i) >= (int)(n);--(i))
#define reper(i, a, n) for(int i = (int)(a);(i) >= (int)(n);--(i))
#define SZ(x) ((int)(x).size())
#define ALL(x) begin(x), end(x)
#define CEIL(x) ((int)ceil(((double)x)))
#define POW(x, y) ((int)pow(x, y))
#define UNIQUE(x) (x).erase(unique(ALL((x))), end(x))
#define gcd(x, y) __gcd(x, y)
#define lcm(x, y) ((x)/gcd(x,y)*(y))
#define isin(x, l, r) ((l) <= (x) and (x) < (r))
#define fcout(n) cout << fixed << setprecision(n)
#define rcout(n) cout << right << setw(n)
#define pb push_back
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define PI (acosl(-1))
#define EPS (1e-10)
#define INF LLONG_MAX
#define INF32 INT32_MAX
#define MOD 1000000007LL
using namespace std;
using VI = vector<int>;
using PII = pair<int, int>;
using TIII = tuple<int, int, int>;
using VPII = vector<PII>;
using VTIII = vector<TIII>;
using Complex = complex<double>;
template<typename T, template<typename> typename C = less> using PQ = priority_queue<T, vector<T>, C<T>>;
template<typename T> inline bool chmax(T& a, const T& b, bool t = false){ if(a<b or (t and a == b)){ a=b; return true; } return false; }
template<typename T> inline bool chmin(T& a, const T& b, bool t = false){ if(a>b or (t and a == b)){ a=b; return true; } return false; }


signed main(){
    int w, h;
    while(cin >> w >> h, w+h){
        vector<VI> hor(h), ver(w);
        rep(i, 0, h) hor[i].pb(1);
        rep(i, 0, w) ver[i].pb(i != 0);
        rep(i, 0, 2*h-1){
            int x;
            if(i%2 == 0) rep(j, 0, w-1) cin >> x, hor[i/2].pb(x);
            else rep(j, 0, w) cin >> x, ver[j].pb(x);
        }
        rep(i, 0, h) hor[i].pb(1);
        rep(i, 0, w) ver[i].pb(i != w-1);
        vector<VI> d(h, VI(w));
        queue<PII> q;
        q.push({ 0, 0 });
        d[0][0] = 1;
        while(!q.empty()){
            PII p = q.front(); q.pop();
            int y = p.first, x = p.second;
            if(isin(y, 0, h) and isin(x+1, 0, w) and hor[y][x+1] == 0 and d[y][x+1] == 0) d[y][x+1] = d[y][x]+1, q.push({ y, x+1 });
            if(isin(y+1, 0, h) and isin(x, 0, w) and ver[x][y+1] == 0 and d[y+1][x] == 0) d[y+1][x] = d[y][x]+1, q.push({ y+1, x });
            if(isin(y, 0, h) and isin(x-1, 0, w) and hor[y][x] == 0 and d[y][x-1] == 0) d[y][x-1] = d[y][x]+1, q.push({ y, x-1 });
            if(isin(y-1, 0, h) and isin(x, 0, w) and ver[x][y] == 0 and d[y-1][x] == 0) d[y-1][x] = d[y][x]+1, q.push({ y-1, x });
        }
        cout << d[h-1][w-1] << endl;
    }

    return 0;
}