#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 800;
vector <string> field(MAX_N);
bool bees_visited[MAX_N][MAX_N], mecho_visited[MAX_N][MAX_N];
int dis[MAX_N][MAX_N];
queue <pair <int, int>> mecho_q, bees_q;
int n, s;
bool valid_sq(int x, int y, bool mecho){
if (x >= 0 && x < n && y >= 0 && y < n){
if (mecho && (field[x][y] == 'G' || field[x][y] == 'D' || field[x][y] == 'M'))
return true;
else if (!mecho && (field[x][y] == 'G' || field[x][y] == 'H'))
return true;
return false;
}
return false;
}
void move_bees(int x, int y, bool add){
if (valid_sq(x-1, y, false) && !bees_visited[x-1][y]){
if (add)
bees_q.push({x-1, y});
bees_visited[x-1][y] = true;
}
if (valid_sq(x+1, y, false) && !bees_visited[x+1][y]){
if (add)
bees_q.push({x+1, y});
bees_visited[x+1][y] = true;
}
if (valid_sq(x, y-1, false) && !bees_visited[x][y-1]){
if (add)
bees_q.push({x, y-1});
bees_visited[x][y-1] = true;
}
if (valid_sq(x, y+1, false) && !bees_visited[x][y+1]){
if (add)
bees_q.push({x, y+1});
bees_visited[x][y+1] = true;
}
}
void move_mecho(int x, int y, bool add){
if (valid_sq(x-1, y, true) && !mecho_visited[x-1][y] && !bees_visited[x-1][y]){
mecho_visited[x-1][y] = true;
if (add)
mecho_q.push({x-1, y});
}
if (valid_sq(x+1, y, true) && !mecho_visited[x+1][y] && !bees_visited[x+1][y]){
mecho_visited[x+1][y] = true;
if (add)
mecho_q.push({x+1, y});
}
if (valid_sq(x, y-1, true) && !mecho_visited[x][y-1] && !bees_visited[x][y-1]){
mecho_visited[x][y-1] = true;
if (add)
mecho_q.push({x, y-1});
}
if (valid_sq(x, y+1, true) && !mecho_visited[x][y+1] && !bees_visited[x][y+1]){
mecho_visited[x][y+1] = true;
if (add)
mecho_q.push({x, y+1});
}
}
void mecho_bfs(){
while (!mecho_q.empty() && dis[mecho_q.front().first][mecho_q.front().second] < s){
int x = mecho_q.front().first, y = mecho_q.front().second;
mecho_q.pop();
if (dis[x][y] >= s){
mecho_q.push({x, y});
continue;
}
if (valid_sq(x-1, y, true) && !mecho_visited[x-1][y] && !bees_visited[x-1][y] && dis[x][y] + 1 <= s){
mecho_visited[x-1][y] = true;
mecho_q.push({x-1, y});
dis[x-1][y] = dis[x][y] + 1;
}
if (valid_sq(x+1, y, true) && !mecho_visited[x+1][y] && !bees_visited[x+1][y] && dis[x][y] + 1 <= s){
mecho_visited[x+1][y] = true;
mecho_q.push({x+1, y});
dis[x+1][y] = dis[x][y] + 1;
}
if (valid_sq(x, y-1, true) && !mecho_visited[x][y-1] && !bees_visited[x][y-1] && dis[x][y] + 1 <= s){
mecho_visited[x][y-1] = true;
mecho_q.push({x, y-1});
dis[x][y-1] = dis[x][y] + 1;
}
if (valid_sq(x, y+1, true) && !mecho_visited[x][y+1] && !bees_visited[x][y+1] && dis[x][y] + 1 <= s){
mecho_visited[x][y+1] = true;
mecho_q.push({x, y+1});
dis[x][y+1] = dis[x][y] + 1;
}
}
}
int main()
{
// freopen("in.txt", "r", stdin);
// freopen("out.txt", "w", stdout);
cin >> n >> s;
for (int i = 0; i < n; i++)
cin >> field[i];
vector <pair <int, int>> hives;
int startx, starty, home_x, home_y;
//find Mecho's position
for (int i = 0; i < n; i++){
for (int j = 0; j < n; j++){
if (field[i][j] == 'M'){
startx = i;
starty = j;
}else if (field[i][j] == 'H'){
hives.push_back({i, j});
}else if (field[i][j] == 'D'){
home_x = i;
home_y = j;
}
}
}
int l = 0, r = n + n - 2;
while (l <= r){
int eating_time = (l + r) / 2;
memset(bees_visited, false, sizeof(bees_visited));
memset(mecho_visited, false, sizeof(mecho_visited));
//simulate
//move only bees, since mecho is eating
for (auto i : hives){
bees_q.push({i.first, i.second});
bees_visited[i.first][i.second] = true;
}
for (int i = 0; i < eating_time; i++){
int si = bees_q.size();
for (int j = 0; j < si; j++){
move_bees(bees_q.front().first, bees_q.front().second, true);
bees_q.pop();
}
}
//move mecho and bees
mecho_q.push({startx, starty});
for (int i = eating_time; i < 2 * n - 2; i++){
mecho_bfs();
memset(dis, 0, sizeof(dis));
int si = bees_q.size();
for (int j = 0; j < si; j++){
move_bees(bees_q.front().first, bees_q.front().second, true);
bees_q.pop();
}
}
if (mecho_visited[home_x][home_y])
l = eating_time + 1;
else
r = eating_time - 1;
//empty both queues
while (!bees_q.empty())
bees_q.pop();
while (!mecho_q.empty())
mecho_q.pop();
}
cout << r << '\n';
}
