import java.util.*;
import java.io.*;
import java.math.BigDecimal;
import java.awt.geom.*;
import static java.util.Arrays.*;
import static java.lang.Math.*;

public class Main{

    static final Reader sc = new Reader();
    static final PrintWriter out = new PrintWriter(System.out,false);

    public static void main(String[] args) throws Exception {
        while(true){
        	int w = sc.nextInt();
        	int h = sc.nextInt();
        	if(w==0 && h==0){
        		break;
        	}
        	int[][] wi = new int[h][w-1];
        	int[][] hi = new int[h-1][w];
        	for(int i=0;i<w-1;i++){
        		wi[0][i] = sc.nextInt();
        	}
        	for(int i=0;i<h-1;i++){
        		for(int j=0;j<w;j++){
        			hi[i][j] = sc.nextInt();
        		}
        		for(int l=0;l<w-1;l++){
        			wi[i+1][l] = sc.nextInt();
        		}
        	}
        	ArrayList<Point> list1 = new ArrayList<Point>();
        	ArrayList<Point> list2 = new ArrayList<Point>();
        	boolean[][] judge = new boolean[h][w];
        	Point p = new Point(0,0);
        	list1.add(p);
        	judge[0][0] = true;
        	int[] dx = {-1,0,1,0};
        	int[] dy = {0,-1,0,1};
        	int count = 2;
        	int ans = 0;
        	while(true){
        		while(!list1.isEmpty()){
        			p = list1.get(0);
        			list1.remove(0);
        			for(int i=0;i<4;i++){
        				if(p.x==0 && i==0){
        					continue;
        				}
        				if(p.x==w-1 && i==2){
        					continue;
        				}
        				if(p.y==0 && i==1){
        					continue;
        				}
        				if(p.y==h-1 && i==3){
        					continue;
        				}
        				if(!judge[p.y+dy[i]][p.x+dx[i]]){
        					if(i==0 && wi[p.y+dy[i]][p.x+dx[i]]==0){
                                judge[p.y+dy[i]][p.x+dx[i]] = true;
                                Point pp = new Point(p.x+dx[i],p.y+dy[i]);
                                list2.add(pp);
        					}
                            if(i==2 && wi[p.y+dy[i]][p.x+dx[i]-1]==0){
                                if(p.x+dx[i]==w-1 && p.y+dy[i]==h-1){
                                    ans = count;
                                    list1.clear();
                                    list2.clear();
                                    break;
                                }
                                judge[p.y+dy[i]][p.x+dx[i]] = true;
                                Point pp = new Point(p.x+dx[i],p.y+dy[i]);
                                list2.add(pp);
                            }
        					if(i==1 && hi[p.y+dy[i]][p.x+dx[i]]==0){
                                judge[p.y+dy[i]][p.x+dx[i]] = true;
                                Point pp = new Point(p.x+dx[i],p.y+dy[i]);
                                list2.add(pp);	
                            }
                            if(i==3 && hi[p.y+dy[i]-1][p.x+dx[i]]==0){
                                if(p.x+dx[i]==w-1 && p.y+dy[i]==h-1){
                                    ans = count;
                                    list1.clear();
                                    list2.clear();
                                    break;
                                }
                                judge[p.y+dy[i]][p.x+dx[i]] = true;
                                Point pp = new Point(p.x+dx[i],p.y+dy[i]);
                                list2.add(pp);
                            }
        				}
        			}
        		}
                if(list2.isEmpty()){
        			break;
        		}
        		count++;
        		for(int k=0;k<list2.size();k++){
        			list1.add(list2.get(k));
        		}
        		list2.clear();
        	}
        	out.println(ans);
        	out.flush();
        }
        sc.close();
        out.close();
    }

    static void trace(Object... o) { System.out.println(Arrays.deepToString(o));}
}

class Point{
	int x;
	int y;
	Point(int x,int y){
		this.x = x;
		this.y = y;
	}
}

class Reader {
    private final InputStream sc;
    private final byte[] buf = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;

    public Reader() { this(System.in);}
    public Reader(InputStream source) { this.sc = source;}

    private boolean hasNextByte() {
        if (ptr < buflen) return true;
        ptr = 0;
        try{
            buflen = sc

.read(buf);
        }catch (IOException e) {e.printStackTrace();}
        if (buflen <= 0) return false;
        return true;
    }

    private int readByte() { if (hasNextByte()) return buf[ptr++]; else return -1;}

    private boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}

    private void skip() { while(hasNextByte() && !isPrintableChar(buf[ptr])) ptr++;}

    public boolean hasNext() {skip(); return hasNextByte();}

    public String next() {
        if (!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while (isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }

    public long nextLong() {
        if (!hasNext()) throw new NoSuchElementException();
        boolean minus = false;
        long num = readByte();

        if(num == '-'){
            num = 0;
            minus = true;
        }else if (num < '0' || '9' < num){
            throw new NumberFormatException();
        }else{
            num -= '0';
        }
        
        while(true){
            int b = readByte();
            if('0' <= b && b <= '9')
                num = num * 10 + (b - '0');
            else if(b == -1 || !isPrintableChar(b))
                return minus ? -num : num;
            else
                throw new NoSuchElementException();
        }
    }

    public int nextInt() {
        long num = nextLong();
        if (num < Integer.MIN_VALUE || Integer.MAX_VALUE < num)
            throw new NumberFormatException();
        return (int)num;
    }

    public double nextDouble() {
        return Double.parseDouble(next());
    }

    public char nextChar() {
        if (!hasNext()) throw new NoSuchElementException();
        return (char)readByte();
    }

    public String nextLine() {
        while (hasNextByte() && (buf[ptr] == '\n' || buf[ptr] == '\r')) ptr++;
        if (!hasNextByte()) throw new NoSuchElementException();

        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while (b != '\n' && b != '\r') {
            sb.appendCodePoint(b);
            b = readByte();
        }

        return sb.toString();
    }

    public int[] nextIntArray(int n) {
        int[] res = new int[n];
        for (int i=0; i<n; i++) res[i] = nextInt();
        return res;
    }

    public char[] nextCharArray(int n) {
        char[] res = new char[n];
        for (int i=0; i<n; i++) res[i] = nextChar();
        return res;
    }

    public void close() {try{ sc.close();}catch(IOException e){ e.printStackTrace();}};
}

Measured memory_bytes: 30644