#include <stdio.h>

int dmap[4][2] = { { -1, 0 }, { 1, 0 }, { 0, -1 }, { 0, 1 } };

int main () {
  int h = 0;
  int w = 0;
  char s[400][401] = {};
  
  int res = 0;
  
  int is_ok = 0;
  
  int r[400][400] = {};
  int org_flag[400][400] = {};
  int flag[400][400] = {};
  
  int q[2400][2] = {};
  int q_hd = 0;
  int q_tl = 0;
  
  res = scanf("%d", &h);
  res = scanf("%d", &w);
  for (int i = 0; i < h; i++) {
    res = scanf("%s", s[i]);
  }
  
  for (int i = 0; i < h-2; i++) {
    for (int j = 0; j < w-2; j++) {
      for (int k = 0; k < 3; k++) {
        for (int l = 0; l < 3; l++) {
          if (s[i+k][j+l] == '#') {
            flag[i][j] = 1;
            org_flag[i][j] = 1;
          }
        }
      }
    }
  }
  
  r[0][0] = 1;
  q[q_tl][0] = 0;
  q[q_tl][1] = 0;
  q_tl++;
  while (q_hd < q_tl) {
    int ci = q[q_hd][0];
    int cj = q[q_hd][1];
    q_hd++;
    for (int i = 0; i < 4; i++) {
      int ni = ci+dmap[i][0];
      int nj = cj+dmap[i][1];
      if (ni >= 0 && ni < h-2 && nj >= 0 && nj < w-2 && flag[ni][nj] == 0 && r[ni][nj] <= 0) {
        r[ni][nj] = 1;
        q[q_tl][0] = ni;
        q[q_tl][1] = nj;
        q_tl++;
      }
    }
  }
  
  if (r[h-3][w-3] <= 0) {
    printf("0\n");
    return 0;
  }
  
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if ((i > 2 || j > 2) && (i < h-3 || j < w-3) && s[i][j] == '.') {
        for (int k = 0; k < 3; k++) {
          for (int l = 0; l < 3; l++) {
            if (i-k >= 0 && i-k < h-2 && j-l >= 0 && j-l < w-2) {
              flag[i-k][j-l] = 1;
            }
          }
        }
        for (int i = 0; i < h-2; i++) {
          for (int j = 0; j < w-2; j++) {
            r[i][j] = 0;
          }
        }
        q_hd = 0;
        q_tl = 0;
        r[0][0] = 1;
        q[q_tl][0] = 0;
        q[q_tl][1] = 0;
        q_tl++;
        while (q_hd < q_tl) {
          int ci = q[q_hd][0];
          int cj = q[q_hd][1];
          q_hd++;
          for (int i = 0; i < 4; i++) {
            int ni = ci+dmap[i][0];
            int nj = cj+dmap[i][1];
            if (ni >= 0 && ni < h-2 && nj >= 0 && nj < w-2 && flag[ni][nj] == 0 && r[ni][nj] <= 0) {
              r[ni][nj] = 1;
              q[q_tl][0] = ni;
              q[q_tl][1] = nj;
              q_tl++;
            }
          }
        }
  
        if (r[h-3][w-3] <= 0) {
          is_ok = 1;
        }
    
        for (int i = 0; i < h-2; i++) {
          for (int j = 0; j < w-2; j++) {
            flag[i][j] = org_flag[i][j];
          }
        }
      }
    }
  }
  
  if (is_ok > 0) {
    printf("1\n");
    return 1;
  } else {
    printf("2\n");
  }
  
  return 0;
}