#include <iostream>
#include <vector>
#include <queue>
using namespace std;

vector<int> returnPosibbleMoves(const vector<vector<char>>& map, const int& v, const int& M, const int& N) {
  int x = v % M;
  vector<int> temp;
  int y = v / M;
  if (y == 0) {
    if (x == 0) {
      if (map[y][x + 1] != '+')
        temp.push_back(y * M + x + 1);
      if (map[y + 1][x] != '+')
        temp.push_back(y * M + x + M);
    } else if (x == M - 1) {
      if (map[y + 1][x] != '+')
        temp.push_back(y * M + x + M);
      if (map[y][x - 1] != '+')
        temp.push_back(y * M + x - 1);
    } else {
      if (map[y + 1][x] != '+')
        temp.push_back(y * M + x + M);
      if (map[y][x - 1] != '+')
        temp.push_back(y * M + x - 1);
      if (map[y][x + 1] != '+')
        temp.push_back(y * M + x + 1);
    }
  } else if (y == N - 1) {
    if (x == 0) {
      if (map[y][x + 1] != '+')
        temp.push_back(y * M + x + 1);
      if (map[y - 1][x] != '+')
        temp.push_back(y * M + x - M);
    } else if (x == M - 1) {
      if (map[y - 1][x] != '+')
        temp.push_back(y * M + x - M);
      if (map[y][x - 1] != '+')
        temp.push_back(y * M + x - 1);
    } else {
      if (map[y][x - 1] != '+')
        temp.push_back(y * M + x - 1);
      if (map[y][x + 1] != '+')
        temp.push_back(y * M + x + 1);
      if (map[y - 1][x] != '+')
        temp.push_back(y * M + x - M);
    }
  } else if (x == 0) {
    if (map[y + 1][x] != '+')
      temp.push_back(y * M + x + M);
    if (map[y][x + 1] != '+')
      temp.push_back(y * M + x + 1);
    if (map[y - 1][x] != '+')
      temp.push_back(y * M + x - M);
  } else if (x == M - 1) {
    if (map[y + 1][x] != '+')
      temp.push_back(y * M + x + M);
    if (map[y][x - 1] != '+')
      temp.push_back(y * M + x - 1);
    if (map[y - 1][x] != '+')
      temp.push_back(y * M + x - M);
  } else {
    if (map[y][x + 1] != '+')
      temp.push_back(y * M + x + 1);
    if (map[y + 1][x] != '+')
      temp.push_back(y * M + x + M);
    if (map[y][x - 1] != '+')
      temp.push_back(y * M + x - 1);
    if (map[y - 1][x] != '+')
      temp.push_back(y * M + x - M);
  }
  return temp;
}

int main() {
  int N, M;
  cin >> N >> M;
  vector<vector<char>> map(N);
  for (int i = 0; i < N; ++i) {
    map[i].resize(M);
  }
  int s = 0, f = 0; //start and finish

  for (int i = 0; i < N; ++i) {
    for (int j = 0; j < M; ++j) {
      cin >> map[i][j];
      if (map[i][j] == '@')
        s = i * M + j;
      else if (map[i][j] == '#')
        f = i * M + j;
    }
  }

  bool a = false;

  queue<int> q;
  q.push(s);
  vector<bool> used(N * M);
  vector<int> d(N * M);
  used[s] = true;
  while (!q.empty()) {
    int v = q.front();
    q.pop();
    vector<int> temp = returnPosibbleMoves(map, v, M, N);
    for (unsigned long int i = 0; i < temp.size(); ++i) {
      int to = temp[i];
      if (!used[to]) {
        used[to] = true;
        q.push(to);
        d[to] = d[v] + 1;
        if (to == f) {
          a = true;
          cout << d[to];
        }
      }
    }
  }

  if (!a)
    cout << -1;
}