static int N, M;

static int[] dx = {1, -1, 0, 0}; // 동서남북

static int[] dy = {0, 0, -1, 1};

static char[][] matrix;

static int[][] count;

static boolean[][] isVisit;

public static void main(String[] args) throws IOException {

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

StringTokenizer st = new StringTokenizer(br.readLine());

N = Integer.parseInt(st.nextToken());

M = Integer.parseInt(st.nextToken());

matrix = new char[N][];

count = new int[N][M];

isVisit = new boolean[N][M];

for (int i = 0; i < N; i++) {

matrix[i] = br.readLine().toCharArray();

}

// (0, 0) 방문

count[0][0] = 1;

bfs(0, 0);

bw.write(count[N-1][M-1] + "");

bw.flush();

bw.close();

}

public static void bfs(int x, int y) {

Queue<int[]> q = new LinkedList<>();

q.offer(new int[] {x, y});

while(!q.isEmpty()) {

int[] next = q.poll();

isVisit[x][y] = true;

for (int i = 0; i < 4; i++) { // 동서남북 검사

int nextX = next[0] + dx[i];

int nextY = next[1] + dy[i];

if (nextX >= 0 && nextY >= 0 && nextX < N && nextY < M) {

if(!isVisit[nextX][nextY] && matrix[nextX][nextY] == '1') {

// 해당 노드 방문 가능

q.offer(new int[] {nextX, nextY});

isVisit[nextX][nextY] = true;

count[nextX][nextY] = count[next[0]][next[1]] + 1;

}

}

}

}

}