#include <iostream>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <queue>
#include <set>
#include <map>

using namespace std;
typedef long long ll;
typedef pair<int, int> Pii;
typedef pair<ll, Pii> P;

int H, W;
char a[2000][2000];
ll dist[2000][2000];
ll dist1[2000][2000];
const ll INF = 1e15;
int dh[4] = {-1, 1, 0, 0};
int dw[4] = {0, 0, -1, 1};

bool in_field(int h, int w){
    return h >= 0 && h < H && w >= 0 && w < W;
}

void dijkstra(){
    priority_queue<P, vector<P>, greater<P>> que;
    for(int i = 0; i < H; i++){
        for(int j = 0; j < W; j++){
            dist[i][j] = INF;
        }
    }
    dist[0][0] = 0;
    que.push(P(0, Pii(0, 0)));
    while(!que.empty()){
        P p = que.top();que.pop();
        Pii v = p.second;
        int h = v.first, w = v.second;
        if(dist[h][w] < p.first) continue;
        for(int i = 0; i < 4; i++){
            int h_to = h+dh[i], w_to = w+dw[i];
            if(!in_field(h_to, w_to)) continue;
            ll cost = (a[h][w] == '.' ? 1 : (dist1[h][w]+1));
            if(dist[h][w] + cost < dist[h_to][w_to]){
                dist[h_to][w_to] = dist[h][w] + cost;
                dist1[h_to][w_to] = dist1[h][w] + 1;
                que.push(P(dist[h_to][w_to], Pii(h_to, w_to)));
            }
        }
    }
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << setprecision(10) << fixed;
    cin >> H >> W;
    for(int i = 0; i < H; i++){
        for(int j = 0; j < W; j++){
            cin >> a[i][j];
        }
    }
    dijkstra();
    cout << dist[H-1][W-1] << endl;
}