#include<iostream>
#include<queue>
#include<utility>
#define WHITE 0
#define GRAY 1
#define BLACK 2
#define mp make_pair
#define INF (1 << 30)
using namespace std;
typedef pair<int, int> cood;

int tate[33][33], yoko[33][33];
int check[33][33];

void solve(int w, int h) {
    int idx = 0;
    for (int i = 0; i < 2 * h - 1; i++) {
        if (i % 2 == 0) {
            for (int j = 0; j < w - 1; j++) {
                cin >> tate[idx][j];
            }
        }
        else {
            for (int j = 0; j < w; j++) {
                cin >> yoko[idx][j];
            }
            idx++;
        }
    }
    for (int i = 0; i < h; i++) {
        for (int j = 0; j < w; j++) check[i][j] = WHITE;
    }
    queue<pair<cood, int> > Q;
    int dh[4] = {0, 1, 0, -1}, dw[4] = {-1, 0, 1, 0};
    cood now_cood = mp(0, 0);
    int min_dist = INF;
    Q.push(mp(now_cood, 1));
    check[0][0] = GRAY;
    
    while (! Q.empty()) {
        pair<cood, int> now_info = Q.front();
        now_cood = now_info.first;
        Q.pop();
        check[now_cood.first][now_cood.second] = BLACK;
        if (now_cood.first == h - 1 && now_cood.second == w - 1 && min_dist > now_info.second) {
            min_dist = now_info.second;
        }
        for (int i = 0; i < 4; i++) {
            int nh = now_cood.first + dh[i], nw = now_cood.second + dw[i];
            if (nh >= 0 && nh < h && nw >= 0 && nw < w && check[nh][nw] == WHITE) {
                if (i == 0) {
                    if (now_cood.second - 1 >= 0) {
                        if (tate[now_cood.first][now_cood.second - 1] != 1) {
                            Q.push(mp(mp(nh, nw), now_info.second + 1));
                            check[nh][nw] = GRAY;
                        }
                    }
                    else {
                        Q.push(mp(mp(nh, nw), now_info.second + 1));
                        check[nh][nw] = GRAY;
                    }
                }
                else if (i == 1) {
                    if (now_cood.first < h - 1) {
                        if (yoko[now_cood.first][now_cood.second] != 1) {
                            Q.push(mp(mp(nh, nw), now_info.second + 1));
                            check[nh][nw] = GRAY;
                        }
                    }
                    else {
                        Q.push(mp(mp(nh, nw), now_info.second + 1));
                        check[nh][nw] = GRAY;
                    }
                }
                else if (i == 2) {
                    if (now_cood.second < w - 1) {
                        if (tate[now_cood.first][now_cood.second] != 1) {
                            Q.push(mp(mp(nh, nw), now_info.second + 1));
                            check[nh][nw] = GRAY;
                        }
                    }
                    else {
                        Q.push(mp(mp(nh, nw), now_info.second + 1));
                        check[nh][nw] = GRAY;
                    }
                }
                else {
                    if (now_cood.first - 1 >= 0) {
                        if (yoko[now_cood.first - 1][now_cood.second] != 1) {
                            Q.push(mp(mp(nh, nw), now_info.second + 1));
                            check[nh][nw] = GRAY;
                        }
                    }
                    else {
                        Q.push(mp(mp(nh, nw), now_info.second + 1));
                        check[nh][nw] = GRAY;
                    }
                }
            }
        }
    }
    if (min_dist == INF) cout << 0 << endl;
    else cout << min_dist << endl;
    return;
}

int main() {
    int w, h;
    while (1) {
        cin >> w >> h;
        if (w == 0 && h == 0) {
            break;
        }
        else solve(w, h);
    }
    return 0;
}



Measured memory_bytes: 3128