#include <cstdio>
#include <queue>

using namespace std;

const int dx[4] = {-1, 1, 0, 0};
const int dy[4] = {0, 0, -1, 1};

bool map[100][100], visited[100][100];

int bfs(int N, int M) {
    queue<int> Q;
    Q.push(0);

    int res = 1;
    bool flag = false;
    visited[0][0] = true;

    while (true) {
        int que_size = (int) Q.size();
        for (int i = 0; i < que_size; i++) {
            int x = Q.front() / 100;
            int y = Q.front() % 100;
            Q.pop();

            if (x == N - 1 && y == M - 1) {
                flag = true;
            }

            for (int d = 0; d < 4; d++) {
                int now_x = x + dx[d];
                int now_y = y + dy[d];
                if (now_x < 0 || now_x >= N || now_y < 0 || now_y >= M) {
                    continue;
                }
                if (!map[now_x][now_y]) {
                    continue;
                }
                if (visited[now_x][now_y]) {
                    continue;
                }
                visited[now_x][now_y] = true;
                Q.push(now_x * 100 + now_y);
            }
        }
        if (flag) {
            break;
        }

        res++;
    }
    return res;
}

int main(int argc, const char *argv[]) {
    int N, M;
    scanf("%d %d", &N, &M);
    for (int i = 0; i < N; i++) {
        for (int j = 0; j < M; j++) {
            scanf("%1d", &map[i][j]);
        }
    }
    printf("%d\n", bfs(N, M));

    return 0;
}