#include <iostream>
#include <string>
#include <cstring>
#include <vector>
#include <algorithm>
#include <tuple>
#include <queue>
#include <set>
#include <cstdio>
#include <climits>
#include <cmath>
#include <array>
#include <functional>
#include <sstream>
#include <list>
#include <set>
const int MOD=1000000007;
const int INF=1000000000;
using namespace std;
typedef long long ll;
typedef vector<int> vi;
const double eps=1e-9;
const int inf=1e9;
typedef pair<int,int> P;
struct Point
{
  double x,y;
  Point(){x=0;y=0;}
  Point(double d_x,double d_y){x=d_x,y=d_y;}
  double operator*(Point obj){return obj.x*x+obj.y*y;}
  double operator%(Point obj){return obj.y*x-obj.x*y;}
  Point operator*(double b){Point tmp;tmp.x=x*b;tmp.y=y*b;return tmp;}
  Point operator/(double b){Point tmp;tmp.x=x/b;tmp.y=y/b;return tmp;}
  Point operator+(Point obj){Point tmp;tmp.x=x+obj.x;tmp.y=y+obj.y;return tmp;}
  Point operator-(){Point tmp;tmp.x=-x;tmp.y=-y;return tmp;}
  Point operator-(Point obj){Point tmp;tmp.x=x-obj.x;tmp.y=y-obj.y;return tmp;}
  Point operator-=(Point obj){x-=obj.x;y-=obj.y;return *this;}
  Point operator+=(Point obj){x+=obj.x;y+=obj.y;return *this;}
  Point operator/=(double b){x=x/b;y=y/b;return *this;}
  Point operator*=(double b){x=x*b;y=y*b;return *this;}
  double size(){return hypot(x,y);}
  Point unit(){return Point(x/size(),y/size());}
  Point normal(){return Point(y,-x);}
  double atan(){return atan2(y,x);}
};

bool operator<(Point a,Point b){return a.x!=b.x?a.x<b.x:a.y<b.y;}
bool operator>(Point a,Point b){return b<a;}
bool operator<=(Point a,Point b){return !(b<a);}
bool operator>=(Point a,Point b){return !(a<b);}
bool operator==(Point a,Point b){return (a-b).size()<eps;}
bool operator!=(Point a,Point b){return !(a==b);}

bool equal(double a,double b){return abs(a-b)<eps;}
double cross(Point a,Point b){return a%b;}
double dot(Point a,Point b){return a*b;}

int ccw(Point a,Point b,Point c)
{
  b=b-a;
  c=c-a;
  if(b%c>0) return +1;
  else if(b%c<0)return -1;
  else if(b*c<0) return +2;
  else if(b.size()<c.size()) return -2;
  else return 0;
}

int w,h;
int board[105][105][4];
int len[105][105];
bool visited[105][105];
int dx[]={-1,0,1,0};
int dy[]={0,-1,0,1};

inline bool outrange(int x,int y)
{
  return (x<0 || x>=w || y<0 || y>=h);
}

void bfs()
{
  len[0][0]=1;
  queue<pair<int,int> > q;
  q.push(make_pair(0,0));
  visited[0][0]=true;
  while(!q.empty())
    {
      pair<int,int>  now=q.front();
      q.pop();
      int y=now.first;
      int x=now.second;
      if(y==h-1 && x==w-1)
	{
	  cout << len[h-1][w-1] << endl;
	  return;
	}
      for(int k=0;k<4;k++)
	{
	  int ny=y+dy[k],nx=x+dx[k];
	  if(nx>=w || nx<0 || ny>=h || ny<0 || visited[ny][nx] || board[y][x][k]==1) continue;
	  len[ny][nx]=min(len[ny][nx],len[y][x]+1);
	  visited[ny][nx]=true;
	  q.push(make_pair(ny,nx));
	}
    }
  cout << 0 << endl;
}


int main(int argc,char const* argv[])
{
  while(1)
    {
      for(int i=0;i<105;i++)
	{
	  for(int j=0;j<105;j++)
	    {
	      len[i][j]=100000;
	    }
	}
      memset(board,0,sizeof(board));
      memset(visited,false,sizeof(visited));
      cin >> w >> h;
      if(!w && !h)break;
      for(int i=0;i<h-1;i++)
	{
	  for(int j=0;j<w-1;j++)
	    {
	      int tmp;
	      cin >> tmp;
	      if(tmp==1)
		{
		  board[i][j][2]=1;
		  board[i][j+1][0]=1;
		}
	    }
	  for(int j=0;j<w;j++)
	    {
	      int tmp;
	      cin >> tmp;
	      if(tmp==1)
		{
		  board[i][j][3]=1;
		  board[i+1][j][1]=1;
		}
	    }
	}
      for(int j=0;j<w-1;j++)
	{
	  int tmp;
	  cin >> tmp;
	  if(tmp==1)
	    {
	      board[h-1][j][2]=1;
	      board[h-1][j+1][0]=1;
	    }
	}
      bfs();
    }
  return 0;
}



Measured memory_bytes: 3300