#include <bits/stdc++.h>
using namespace std;
#define int long long
int n, s, mx, my, hx, hy;
int dx[4] = {0, 0, 1, -1};
int dy[4] = {1, -1, 0, 0};
bool check(int t, vector<vector<char>> grid, vector<vector<int>> btime) {
priority_queue<pair<int, pair<int, int>>> q;
q.push({0, {mx, my}});
vector<vector<int>> dist(n, vector<int>(n, 0x3f3f3f3f));
dist[mx][my] = 0;
while (!q.empty()) {
auto tp = q.top();
q.pop();
if (grid[tp.second.first][tp.second.second] == 'D') {
return true;
}
for (int i = 0; i < 4; i++) {
int nx = dx[i] + tp.second.first;
int ny = dy[i] + tp.second.second;
if (nx < 0 || nx >= n || ny < 0 || ny >= n) continue;
if (grid[nx][ny] == 'T' || (btime[nx][ny] - t)< -tp.first / 2) continue;
if (dist[nx][ny] > 1 - tp.first) {
dist[nx][ny] = 1 - tp.first;
q.push({tp.first - 1, {nx, ny}});
}
}
}
for (int i = 0; i < 4; i++) {
int nx = dx[i] + hx;
int ny = dy[i] + hy;
if (nx < 0 || nx >= n || ny < 0 || ny >= n) continue;
if (dist[nx][ny] != 0x3f3f3f3f) return true;
}
return false;
}
signed main() {
cin >> n >> s;
vector<vector<char>> grid(n, vector<char>(n));
priority_queue<pair<int, pair<int, int>>> q;
vector<vector<int>> btime(n, vector<int>(n, 0x3f3f3f3f));
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
cin >> grid[i][j];
if (grid[i][j] == 'H') {
btime[i][j] = 0;
q.push({0, {i, j}});
}
if (grid[i][j] == 'M') mx = i, my = j;
if (grid[i][j] == 'D') hx = i, hy = j;
}
}
while (!q.empty()) {
auto tp = q.top();
q.pop();
if (btime[tp.second.first][tp.second.second] != -tp.first) continue;
for (int i = 0; i < 4; i++) {
int nx = dx[i] + tp.second.first;
int ny = dy[i] + tp.second.second;
if (nx < 0 || nx >= n || ny < 0 || ny >= n) continue;
if (grid[nx][ny] != 'G' && grid[nx][ny] != 'M') continue;
if (-tp.first + 1 < btime[nx][ny]) {
btime[nx][ny] = 1 - tp.first;
q.push({-1 + tp.first, {nx, ny}});
}
}
}
int l = 0;
int r = 1e9 + 1;
while (l != r) {
int mid = (l + r + 1)/2;
if (check(mid, grid, btime)) {
l = mid;
}
else {
r = mid - 1;
}
}
cout << l << endl;
}
