Counting Rooms

#include <bits/stdc++.h>

using namespace std;

const int N = 1003;

int n, m;
int vis[N][N];
char c[N][N];

void dfs(int x, int y) {
    vis[x][y] = 1;
    if (c[x - 1][y] == '.' && vis[x - 1][y] == 0) {
        dfs(x - 1, y);
    }
    if (c[x + 1][y] == '.' && vis[x + 1][y] == 0) {
        dfs(x + 1, y);
    }
    if (c[x][y - 1] == '.' && vis[x][y - 1] == 0) {
        dfs(x, y - 1);
    }
    if (c[x][y + 1] == '.' && vis[x][y + 1] == 0) {
        dfs(x, y + 1);
    }
}

int main(){
    cin >> n >> m;

    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            cin >> c[i][j];
        }
    }

    int ans = 0;
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            if (c[i][j] == '.' && vis[i][j] == 0) {
                dfs(i, j);
                ans++;
            }
        }
    }

    cout << ans << endl;
}