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>
using namespace std;

typedef pair<long long int, pair<long long int, long long int>> PLPLL;

int main() {
	long long int N, M;
	while( cin >> N >> M, N || M ) {
		vector<vector<bool>>d( M - 1, vector<bool>( N ) );
		vector<vector<bool>>e( M, vector<bool>( N - 1 ) );
		for( size_t i = 0; i < M + M - 1; i++ ) {
			if( !(i % 2) ) {
				for( size_t j = 0; j < N - 1; j++ ) {
					int k;
					cin >> k;
					e[i / 2][j] = !k;
				}
			} else {
				for( size_t j = 0; j < N; j++ ) {
					int k;
					cin >> k;
					d[i / 2][j] = !k;
				}
			}
		}
		vector<vector<long long int>>m( M, vector<long long int>( N, INT_MAX / 6 ) );
		m[0][0] = 0;
		priority_queue<PLPLL, vector<PLPLL>, greater<PLPLL>>que;
		que.push( make_pair( 1, make_pair( 0, 0 ) ) );
		[&] () {
			while( que.size() ) {
				auto now = que.top(); que.pop();
				auto nowp = now.second;
				if( nowp.first == M - 1 && nowp.second == N - 1 ) {
					cout << now.first << endl;
					return;
				}
				if( nowp.first != M - 1 ) {
					if( d[nowp.first][nowp.second] ) {
						auto next = now;
						next.first++;
						next.second.first++;
						if( m[next.second.first][next.second.second] > next.first ) {
							m[next.second.first][next.second.second] = next.first;
							que.push( next );
						}
					}
				}
				if( nowp.second != N - 1 ) {
					if( e[nowp.first][nowp.second] ) {
						auto next = now;
						next.first++;
						next.second.second++;
						if( m[next.second.first][next.second.second] > next.first ) {
							m[next.second.first][next.second.second] = next.first;
							que.push( next );
						}
					}
				}
				if( nowp.first != 0 ) {
					if( d[nowp.first - 1][nowp.second] ) {
						auto next = now;
						next.first++;
						next.second.first--;
						if( m[next.second.first][next.second.second] > next.first ) {
							m[next.second.first][next.second.second] = next.first;
							que.push( next );
						}
					}
				}
				if( nowp.second != 0 ) {
					if( e[nowp.first][nowp.second - 1] ) {
						auto next = now;
						next.first++;
						next.second.second--;
						if( m[next.second.first][next.second.second] > next.first ) {
							m[next.second.first][next.second.second] = next.first;
							que.push( next );
						}
					}
				}
			}
			cout << 0 << endl;
			return;
		}();
	}
}

C++: #include <cstdio>
#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <string>
#include <cstring>
#include <sstream>
#include <algorithm>
#include <functional>
#include <queue>
#include <stack>
#include <cmath>
#include <iomanip>
#include <list>
#include <tuple>
#include <bitset>

using namespace std;

inline int toInt(string s) { int v; istringstream sin(s); sin >> v; return v; }
inline bool cheak(int x, int y, int xMax, int yMax){ return x >= 0 && y >= 0 && xMax > x && yMax > y; }
template<class T> inline string toString(T x) { ostringstream sout; sout << x; return sout.str(); }
template<class T> inline T sqr(T x) { return x*x; }

typedef pair<int, int> P;
typedef long long ll;
typedef unsigned long long ull;

#define For(i,a,b)	for(int (i) = (a);i < (b);(i)++)
#define rep(i,n)	For(i,0,n)
#define clr(a)		memset((a), 0 ,sizeof(a))
#define mclr(a)		memset((a), -1 ,sizeof(a))
#define all(a)		(a).begin(),(a).end()
#define sz(a)		(sizeof(a))
#define Fill(a,v)	fill((int*)a,(int*)(a+(sz(a)/sz(*(a)))),v)

const int dx[4] = { -1, 0, 1, 0 }, dy[4] = { 0, 1, 0, -1 };
const int mod = 1000000007;
const int INF = 1e9;

int f[31][31][31][31];

int main()
{
	int w, h;

	while (cin >> w >> h && w){
		clr(f);
		rep(i, h){
			rep(j, w - 1){
				int t;
				cin >> t;
				if (t){
					f[i][j][i][j + 1] = 1;
					f[i][j + 1][i][j] = 1;
				}
			}
			if (i != h - 1)
				rep(j, w){
				int t;
				cin >> t;
				if (t){
					f[i][j][i + 1][j] = 1;
					f[i + 1][j][i][j] = 1;
				}
			}
		}
		queue<P> q;
		q.push(P(0, 0));
		int d[31][31]; clr(d);
		d[0][0] = 1;

		int ans = 0;
		while (q.size()){
			P t = q.front(); q.pop();
			int x = t.first;
			int y = t.second;

			rep(i, 4){
				int tx = x + dx[i];
				int ty = y + dy[i];

				if (cheak(tx, ty, w, h) && !f[y][x][ty][tx] && !d[ty][tx]){
					q.push(P(tx, ty));
					d[ty][tx] = d[y][x] + 1;
				}
			}
		}
		cout << d[h-1][w-1] << endl;
	}
	return 0;
}