#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
using ll = long long ;
using P = pair<ll,ll> ;
const int INF = 1e9;
const int MOD = 1000000007;


int main(){
    int h,w;
    cin >> h >> w;
    vector<string> maze(h);
    rep(i,h) cin >> maze[i];
    vector<vector<int>> dp(h,vector<int>(w,INF));

    rep(i,h)rep(j,w){
        if(i==0 && j==0) dp[i][j] = 0;
        if(maze[i][j] == '.'){
            if(i>0) dp[i][j] = min(dp[i][j],dp[i-1][j] + 1);
            if(j>0) dp[i][j] = min(dp[i][j],dp[i][j-1] + 1);
        }else{
            if(i>0) dp[i][j] = min(dp[i][j],dp[i-1][j] + 1 + i + j);
            if(j>0) dp[i][j] = min(dp[i][j],dp[i][j-1] + 1 + i + j);
        }
    }

    cout << dp[h-1][w-1] << endl;
    return 0;
}