#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <climits>

#define rep(i, m, n) for(int i=int(m);i<int(n);i++)
#define EACH(i, c) for (auto &(i): c)
#define all(c) begin(c),end(c)
#define EXIST(s, e) ((s).find(e)!=(s).end())
#define SORT(c) sort(begin(c),end(c))
#define pb emplace_back
#define MP make_pair
#define SZ(a) int((a).size())

//#define LOCAL 0
//#ifdef LOCAL
//#define DEBUG(s) cout << (s) << endl
//#define dump(x)  cerr << #x << " = " << (x) << endl
//#define BR cout << endl;
//#else
//#define DEBUG(s) do{}while(0)
//#define dump(x) do{}while(0)
//#define BR
//#endif


//改造
typedef long long int ll;
using namespace std;
#define INF (1 << 30)
#define INFl (ll)5e15
#define DEBUG 0 //デバッグする時1にしてね
#define dump(x)  cerr << #x << " = " << (x) << endl
#define MOD 1000000007
//ここから編集する
int W, H;

class Dijkstra {
public:
    struct edge {
        ll to, cost;
    };
    typedef pair<ll, ll> P;//firstは最短距離、secondは頂点の番号

    int V;//超点数
    vector<vector<edge> > G;//グラフ,G[i]はiから出る辺の集合,G[i][j]はiから出る辺のj番目の辺
    vector<ll> d; //最短距離

    //0origin
    Dijkstra(int N) {
        V = N;
        G = vector<vector<edge> >(N);
        d = vector<ll>(N);
    };

    void dijkstra(int s) {
        priority_queue<P, vector<P>, greater<P> > que;
        fill(d.begin(), d.end(), INFl);
        d[s] = 0;
        que.push(P(0, s));

        while (!que.empty()) {
            P p = que.top();
            que.pop();
            ll v = p.second;
            if (d[v] < p.first) continue;
            for (int i = 0; i < G[v].size(); i++) {
                edge e = G[v][i];
                if (d[e.to] > d[v] + e.cost && !(d[e.to] == INFl && d[v] == INFl)) {
                    d[e.to] = d[v] + e.cost;
                    que.push(P(d[e.to], e.to));
                }
            }
        }

    }

    /* 頂点fromに頂点toに達するコストcostの辺を貼る */
    void addEdge(int from, int to, int cost) {
        edge e;
        e.to = to;
        e.cost = cost;
        G[from].push_back(e);
    }
};

int getc(int w, int h) {
    return W * h + w;
}

void solve(int w, int h) {
    W = w;
    H = h;
    Dijkstra dij(w * h);
    rep(i, 0, 2 * h - 1) {
        if (i % 2 == 0) {
            rep(j, 0, w - 1) {
                int tmp;
                cin >> tmp;
                if (tmp == 1) {

                } else {
                    int w1 = j;
                    int h1 = i / 2;
                    int w2 = j + 1;
                    int h2 = i / 2;
                    dij.addEdge(getc(w1, h1), getc(w2, h2), 1);
                    dij.addEdge(getc(w2, h2), getc(w1, h1), 1);
                }
            }
        } else {
            rep(j, 0, w) {
                int tmp;
                cin >> tmp;
                if (tmp == 1) {

                } else {
                    int w1 = j;
                    int h1 = i / 2;
                    int w2 = j;
                    int h2 = i / 2 + 1;

                    dij.addEdge(getc(w1, h1), getc(w2, h2), 1);
                    dij.addEdge(getc(w2, h2), getc(w1, h1), 1);
                }

            }
        }
    }
    dij.dijkstra(0);
    ll ans = dij.d[w * h - 1];
    if (ans == INFl) {
        cout << 0 << endl;
    } else {
        cout << ans + 1 << endl;
    }

}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    while (true) {
        int w, h;
        cin >> w >> h;
        if (w == 0) break;
        solve(w, h);

    }


    return 0;
}



Measured memory_bytes: 3208