import java.util.*;

public class Main{
  public static void main(String[] args) throws Exception {
    Scanner sc=new Scanner(System.in);
    int h = sc.nextInt();
    int w = sc.nextInt();
    int[][] a = new int[h][w];

    for(int i = 0;i < h;i++){
      String s = sc.next();
      for(int j = 0;j < w;j++){
        if(s.charAt(j) == '.'){
          a[i][j]=0;
        }else{
          a[i][j]=1;
        }
      }
    }

    int[][] dp =new int[h][w];
    int INM = 1145141919;
    for(int i = 0;i < h;i++){
      for(int j = 0;j < w;j++){
        dp[i][j]=INM;
      }
    }

    dp[0][0] = 0;
    for(int i = 0;i < h;i++){
      for(int j = 0;j < w;j++){
        if(a[i][j] == 0){
          if (i > 0) {
    				dp[i][j] = Math.min(dp[i][j], dp[i-1][j] + 1);
    			}
    			if (j > 0) {
    				dp[i][j] = Math.min(dp[i][j], dp[i][j-1] + 1);
    			}
        }else{
          if (i > 0){
            dp[i][j] = Math.min(dp[i][j], dp[i-1][j] + 1 + i + j);
          }
          if (j > 0){
            dp[i][j] = Math.min(dp[i][j], dp[i][j-1] + 1 + i + j);
          }
        }
      }
    }
    System.out.println(dp[h - 1][w - 1]);
  }
}