// https://ei1333.github.io/luzhiled/
// http://beet-aizu.hatenablog.com/entry/2017/01/04/113233
// http://www.prefield.com/algorithm/
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using vl = vector<ll>;
using vd = vector<ld>;
using vs = vector<string>;
using vb = vector<bool>;
using vvl = vector<vector<ll>>;
using vvd = vector<vector<ld>>;
using vvs = vector<vector<string>>;
using vvb = vector<vector<bool>>;
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
template<class T> using vc = vector<T>;
template<class T> using vvc = vector<vector<T>>;
using Graph = vector<vector<ll>>;
const ll INF = 1LL << 60;
void init() {cin.tie(0);ios::sync_with_stdio(false);cout << fixed << setprecision(15);}
const ll tl= 1000000007;
#define REP(i, n) for (ll i = 0; i < n; i++)
#define REREP(i, n) for (ll i = n; i >= 0; i--)
#define FOR(i, a, n) for (ll i = a; i < n; i++)
#define REFOR(i, n, a) for (ll i = n; i >= a; i--)
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() ) //被り削除
#define debug cout << "line : " << __LINE__ << " debug" << endl;
#define ini(...) int __VA_ARGS__; in(__VA_ARGS__)
#define inl(...) long long __VA_ARGS__; in(__VA_ARGS__)
#define ind(...) long double __VA_ARGS__; in(__VA_ARGS__)
#define ins(...) string __VA_ARGS__; in(__VA_ARGS__)
#define inc(...) char __VA_ARGS__; in(__VA_ARGS__)
void in(){} template <typename T,class... U> void in(T &t,U &...u){ cin >> t; in(u...);}
void out(){cout << endl;} template <typename T,class... U> void out(const T &t,const U &...u){ cout << t; if(sizeof...(u)) cout << " "; out(u...);}
template<typename T>void die(T x){out(x); exit(0);}
#define in1(A) REP(i,A.size()) in(A[i]);
#define in2(A,B) REP(i,A.size()) in(A[i],B[i]);
#define in3(s,t,u) REP(i,sz(s)){in(s[i] , t[i] , u[i]);}
#define in4(s,t,u,v) REP(i,sz(s)){in(s[i] , t[i] , u[i] , v[i]);}
#define each(x,v) for(auto& x : v)
#define all(v) (v).begin(),(v).end()
#define sz(v) ((int)(v).size())
struct Point{ ld x,y; };
ld dist(Point a, Point b){return sqrt(abs(a.x-b.x)*abs(a.x-b.x)+abs(a.y-b.y)*abs(a.y-b.y));} // ２点間の距離 
ll gcd(ll a, ll b) { return b != 0 ? gcd(b, a % b) : a; }
ll lcm(ll a,ll b){ return a / gcd(a,b) * b;} 
ll fact(ll n){ if(n < 2) return 1; return (n * fact(n-1))%tl; } //階乗
inline ll updiv(ll a,ll b){ return (a + b - 1) / b; } //切り上げ
template<typename T,typename U>ll ceil(T a,U b){return (a + b - 1) / b;}
template <class A, class B> inline bool chmax(A &a, const B &b) { return b > a && (a = b, true); }
template <class A, class B> inline bool chmin(A &a, const B &b) { return b < a && (a = b, true); }
//-------------------------------------------------------------------------------------------------
struct grid{
    ll t,y;
};
int main(){
    init();
    while(1){
        inl(w,h);
        if(w==0&&h==0) break;
        vvl tWall(h,vl(w-1,0));
        vvl yWall(h-1,vl(w,0));
        REP(i,h){
            if(i<h-1){
                 // tWall
                REP(j,w-1){
                    cin>>tWall[i][j];
                }
                // yWall
                REP(j,w){
                    cin>>yWall[i][j];
                }
            }else{
               // tWall
                REP(j,w-1){
                    cin>>tWall[i][j];
                }
            }
        }
        grid start= {0,0};
        grid goal= {h-1,w-1};
        vvl visited(h,vl(w,0));
        vvl ans(h,vl(w,0));
        queue<grid> memo;
        ans[0][0]=1;
        visited[0][0]=1;
        memo.push(start);
        
        while(!memo.empty()){
            grid now= memo.front();
            // out(now.t,now.y);
            if(now.t==goal.t &&now.y==goal.y) break;
            memo.pop();
            REP(k,4){
                ll ii= now.t+ (k*2+1)/3-1;
                ll jj= now.y+ (k*2+1)%3-1;
                if(0<=ii&&ii<h && 0<=jj&&jj<w){ //範囲内か
                    if(!visited[ii][jj]){ //訪れたか
                        if(now.t==ii){ //横移動について
                            if(!tWall[ii][min(now.y,jj)]){ //縦棒の有無
                                visited[ii][jj]=1;
                                ans[ii][jj]= ans[now.t][now.y]+1;
                                memo.push({ii,jj});
                            }
                        }else{ //縦について
                            if(!yWall[min(now.t,ii)][jj]){ //横棒の有無
                                visited[ii][jj]=1;
                                ans[ii][jj]= ans[now.t][now.y]+1;
                                memo.push({ii,jj});
                            }
                        }
                    }
                }
            }
        }
        out(ans[goal.t][goal.y]);
    }
    
}


Measured memory_bytes: 3116