#include<bits/stdc++.h>
using namespace std;
#define vi vector<int>
#define ll long long
#define pii pair<int, int>
int n, s;
char grid[800][800];
queue<pair<int, int>> bees_start;
pair<int, int> mecho, home;
bool possible(int t){
// cout << "t = " << t << endl;
//maybe use set to avoid duplicates
map<pii, int> bee_vis;
map<pii, int> mecho_vis;
queue<pii> bees = bees_start;
queue<pii> frontier;
frontier.push(mecho);
//maybe store bee queues for every t if TLE...
int bees_grid[n][n];
memset(bees_grid, 0, sizeof(bees_grid));
while (t--){
// cout << "initial" << endl;
int sz = (int) bees.size();
for (int _ = 0; _ < sz; _++){
auto bee = bees.front();
bee_vis[bee] = 1;
bees.pop();
if (bee.first > 0 && grid[bee.first - 1][bee.second] == 'G' && !bee_vis[{bee.first - 1, bee.second}]) bees.push({bee.first - 1, bee.second}), bees_grid[bee.first - 1][bee.second] = 1;
if (bee.first < n - 1 && grid[bee.first + 1][bee.second] == 'G' && !bee_vis[{bee.first + 1, bee.second}]) bees.push({bee.first + 1, bee.second}), bees_grid[bee.first + 1][bee.second] = 1;
if (bee.second > 0 && grid[bee.first][bee.second - 1] == 'G' && !bee_vis[{bee.first, bee.second - 1}]) bees.push({bee.first, bee.second - 1}), bees_grid[bee.first][bee.second - 1] = 1;
if (bee.second < n - 1 && grid[bee.first][bee.second + 1] == 'G' && !bee_vis[{bee.first, bee.second + 1}]) bees.push({bee.first, bee.second + 1}), bees_grid[bee.first][bee.second + 1] = 1;
}
// for (int i = 0; i < n; i++){
// for (int j = 0; j < n; j++){
// cout << bees_grid[i][j] << " ";
// }
// cout << endl;
// }
// cout << endl << endl;
}
bool reached_home = false;
while (frontier.size()){
int size = (int) frontier.size();
for (int _ = 0; _ < size; _++){
// cout << frontier.size() << endl;
// cout << "iterating" << endl;
auto pos = frontier.front();
if (pos == home) return true;
frontier.pop();
if (pos.first < 0 || pos.second < 0 || pos.first > n - 1 || pos.second > n - 1 || grid[pos.first][pos.second] == 'T' || bees_grid[pos.first][pos.second]) continue;
// if (pos.second == 2 && pos.first == 2){
// cout << pos.first << " " << pos.second << endl;
// cout << bees_grid[pos.first][pos.second] << endl;
// }
mecho_vis[pos] = true;
queue<pair<pii, int>> tmp_frontier; //let him take pair.second s steps
tmp_frontier.push({pos, 0});
while (tmp_frontier.size()){
auto location = tmp_frontier.front().first;
int steps = tmp_frontier.front().second;
tmp_frontier.pop();
if (location == home) return true;
if (location.first < 0 || location.second < 0 || location.first > n - 1 || location.second > n - 1 || grid[location.first][location.second] == 'T' || bees_grid[location.first][location.second]) continue;
// if (pos.second == 2 && pos.first == 2)
// cout << location.first << " " << location.second << " with " << steps << " steps" << endl;
// mecho_vis[location] = 1;
frontier.push(location);
if (steps +1 <= s){
tmp_frontier.push({{location.first + 1, location.second}, steps + 1});
tmp_frontier.push({{location.first - 1, location.second}, steps + 1});
tmp_frontier.push({{location.first, location.second + 1}, steps + 1});
tmp_frontier.push({{location.first, location.second - 1}, steps + 1});
}
}
// for (int i = 0; i < n; i++){
// for (int j = 0; j < n; j++){
// cout << bees_grid[i][j] << " ";
// }
// cout << endl;
// }
// cout << endl << endl;
}
int sz = (int) bees.size();
for (int _ = 0; _ < sz; _++){
auto bee = bees.front();
bee_vis[bee] = 1;
bees.pop();
if (bee.first > 0 && grid[bee.first - 1][bee.second] == 'G' && !bee_vis[{bee.first - 1, bee.second}]) bees.push({bee.first - 1, bee.second}), bees_grid[bee.first - 1][bee.second] = 1;
if (bee.first < n - 1 && grid[bee.first + 1][bee.second] == 'G' && !bee_vis[{bee.first + 1, bee.second}]) bees.push({bee.first + 1, bee.second}), bees_grid[bee.first + 1][bee.second] = 1;
if (bee.second > 0 && grid[bee.first][bee.second - 1] == 'G' && !bee_vis[{bee.first, bee.second - 1}]) bees.push({bee.first, bee.second - 1}), bees_grid[bee.first][bee.second - 1] = 1;
if (bee.second < n - 1 && grid[bee.first][bee.second + 1] == 'G' && !bee_vis[{bee.first, bee.second + 1}]) bees.push({bee.first, bee.second + 1}), bees_grid[bee.first][bee.second + 1] = 1;
}
// for (int i = 0; i < n; i++){
// for (int j = 0; j < n; j++){
// cout << bees_grid[i][j] << " ";
// }
// cout << endl;
// }
// cout << endl << endl;
}
return reached_home;
}
int main(){
cin >> n >> s;
for (int i = 0; i < n; i++){
for (int j = 0; j < n; j++){
cin >> grid[i][j];
if (grid[i][j] == 'M') mecho = {i, j}, grid[i][j] = 'G';
if (grid[i][j] == 'D') home = {i, j};
if (grid[i][j] == 'H') bees_start.push({i, j});
}
}
int lo = 0, hi = 640000;
while (lo < hi){
int mid = (lo + hi + 1) / 2;
if (possible(mid))
lo = mid;
else hi = mid - 1;
}
cout << lo << endl;
// cout << possible(2) << endl;
// cout << home.first << " " << home.second << endl;
return 0;
}
