#include<bits/stdc++.h>

using namespace std;
typedef long long ll;

const int SIZE = 2020;

char s[SIZE][SIZE];

int dp[SIZE][SIZE];

int main(){ 
  
  int h,w; cin >> h >> w;
  
  for(int i = 0; i < h; i++){
    for(int j = 0; j < w; j++){ 
      cin >> s[i][j];
    }
  }
  
  for(int i = 0; i < SIZE; i++){
    for(int j = 0; j < SIZE; j++){
      dp[i][j] = -1;
    }
  }
  
  dp[0][0] = 0;
  
  for(int i = 1; i < h; i++){
    if(s[i][0] == '.'){ dp[i][0] = dp[i-1][0]+1;}
    else{ dp[i][0] = dp[i-1][0]+1+0+i;}
  }
  
  for(int j = 1; j < w; j++){
    if(s[0][j] == '.'){ dp[0][j] = dp[0][j-1]+1;}
    else{ dp[0][j] = dp[0][j-1]+1+0+j;}
  }
  
  for(int i = 0; i < h; i++){
    for(int j = 0; j < w; j++){
      
      if( dp[i][j] != -1){ continue;}
      
      if( s[i][j] == '.'){  
        dp[i][j] = min(dp[i-1][j],dp[i][j-1])+1;}
      else{
        dp[i][j] = min(dp[i-1][j],dp[i][j-1])+1+0+i+j;}
      
    }
  }
  
  cout << dp[h-1][w-1] << endl;
  
  return 0;
}