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++: 2 3
 1
0 1
 0
1 0
 1
9 4
 1 0 1 0 0 0 0 0
0 1 1 0 1 1 0 0 0
 1 0 1 1 0 0 0 0
0 0 0 0 0 0 0 1 1
 0 0 0 1 0 0 1 1
0 0 0 0 1 1 0 0 0
 0 0 0 0 0 0 1 0
12 5
 1 0 0 0 0 0 0 0 0 0 0
0 0 0 1 1 0 0 0 0 0 0 0
 1 0 1 0 0 0 0 0 0 0 0
0 0 0 0 0 0 1 1 0 0 0 0
 0 0 1 0 0 1 0 1 0 0 0
0 0 0 1 1 0 1 1 0 1 1 0
 0 0 0 0 0 1 0 0 1 0 0
0 0 0 0 0 0 0 0 0 0 0 0
 0 0 0 0 0 0 0 0 1 0 0
0 0

C++: #define  _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <algorithm>
#include <utility>
#include <functional>
#include <cstring>
#include <queue>
#include <stack>
#include <math.h>
#include <iterator>
#include <vector>
#include <string>
#include <set>
#include <math.h>
#include <iostream> 
#include <random>
#include<map>
#include <iomanip>
#include <time.h>
#include <stdlib.h>
#include <list>
#include <typeinfo>
#include <list>
#include <set>
#include <cassert>
#include<fstream>
#include <unordered_map>  
using namespace std;
#define Ma_PI 3.141592653589793
#define eps 0.00000000000000000000000001
#define LONG_INF 10000000000000000
#define GOLD 1.61803398874989484820458
#define MAX_MOD 1000000007
#define REP(i,n) for(long long i = 0;i < n;++i)
int main() {
#define int long long 
	while (true) {
		int n, m;
		cin >> n >> m;
		if (n == 0) return 0;
		int gogo[100][100] = {};
		int cost[100][100] = {};
		REP(i, 100) {
			REP(q, 100) {
				cost[i][q] = 10000;
			}
		}
		for (int i = 0; i < m*2 - 1; ++i) {
			for (int q = (i + 1) % 2; q < 2 * n - 1; q+= 2) {
				cin >> gogo[i][q];
			}
		}
		queue<pair<int, int>> next;
		next.push(make_pair(0, 0));
		cost[0][0] = 0;
		int xe[4] = { 0,0,1,-1 };
		while (next.empty() == false) {
			pair<int, int> now = next.front();
			next.pop();
			for (int i = 0; i < 4; ++i) {
				int now_x = now.first + xe[i];
				int now_y = now.second + xe[3 - i];
				if (now_x >= 0 && now_x < 2 * m - 1 && now_y >= 0 && now_y < 2 * n - 1) {
					if (gogo[now_x][now_y] == 0) {
						int next_x = now_x + xe[i];
						int next_y = now_y + xe[3 - i];
						if (cost[next_x][next_y] == 10000) {
							cost[next_x][next_y] = cost[now.first][now.second] + 1;
							next.push(make_pair(next_x, next_y));
						}
					}
				}
			}
		}
		if (cost[m * 2 - 2][n * 2 - 2] == 10000) {
			cout << 0 << endl;
		}
		else {
			cout << 1 + cost[2 * m - 2][n * 2 - 2] << endl;
		}
	}
}

C++: #include<stdio.h>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <algorithm>
#include <sstream>
#include <iostream>
#include <string>

using namespace std;

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

int main() {

	int w, h;
	int map[70][70],dp[35][35];

	while (1) {
		cin >> w >> h;
		if (w==0 && h==0) break;

		int inp;
		for (int i = 0; i < 2 * h - 1; i++) {
			int t = 0;
			if (i % 2 == 0) t = 1;
			for (int j = t; j < 2*w-1; j = j+2) {
				cin >> inp;
				map[i][j] = inp;
			}
		}

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

		dp[0][0] = 1;
		for (int d = 1; d <= w*h; d++) {
			for (int i = 0; i < h; i++) {
				for (int j = 0; j < w; j ++) {
					if (dp[i][j] == d) {
						for (int k = 0; k < 4; k++) {
							int ny = i + dy[k], nx = j + dx[k];
							if (0<=ny && ny<h && 0 <= nx && nx<w) {
								if (map[i + ny][j + nx] == 0 && dp[ny][nx] == -1) {
									dp[ny][nx] = d + 1;
								}
							}
						}
					}
				}
			}
		}

		if(dp[h-1][w-1]==-1) cout << 0 << endl;
		else cout << dp[h - 1][w - 1] << endl;

	}

	return 0;
}