#include <bits/stdc++.h>
using namespace std;
vector<vector<char>> grid;
vector<vector<int>> dist;
pair<int,int> start,dest;
vector<pair<int,int>> hives;
int n,speed;
int dx[] = {1,0,-1,0};
int dy[] = {0,1,0,-1};
bool bfs(int lag) {
if (dist[start.first][start.second]!=-1 && dist[start.first][start.second]<=lag) return false;
vector<vector<int>> walkingdist(n,vector<int>(n,-1));
queue<pair<int,int>> q;
q.push(start);
walkingdist[start.first][start.second]=0;
while (!q.empty()) {
auto [x,y] = q.front();
q.pop();
for (int i=0;i<4;i++) {
int nx = x + dx[i];
int ny = y + dy[i];
if (nx<0 || nx>=n || ny<0 || ny>=n) continue;
if (grid[nx][ny]=='D') {
return true;
}
if (grid[nx][ny]=='T') continue;
if (walkingdist[nx][ny]==-1) {
if (dist[nx][ny]>0){
if ((walkingdist[x][y]+1)/speed+lag<dist[nx][ny]) {
walkingdist[nx][ny]=walkingdist[x][y]+1;
q.push({nx,ny});
}
}
if (dist[nx][ny]==-1 && (grid[nx][ny]=='G' || grid[nx][ny]=='M')) {
walkingdist[nx][ny]=walkingdist[x][y]+1;
q.push({nx,ny});
}
}
}
}
// for (int i=0;i<n;i++) {
// for (int j=0;j<n;j++) {
// cout<<walkingdist[i][j]<<" ";
// }
// cout<<"\n";
// }
// cout<<"\n";
return false;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
//freopen("1.in","r",stdin);
cin>>n>>speed;
grid.resize(n,vector<char>(n));
dist.resize(n,vector<int>(n,-1));
for (int i=0;i<n;i++) {
for (int j=0;j<n;j++) {
cin>>grid[i][j];
if (grid[i][j]=='H') {
hives.push_back({i,j});
dist[i][j]=0;
}
else if (grid[i][j]=='T') {
dist[i][j]=9;
}
else if (grid[i][j]=='M') start={i,j};
else if (grid[i][j]=='D') dest={i,j};
}
}
queue<pair<int,int>> q;
for (auto [x,y]:hives) q.push({x,y});
while (!q.empty()) {
auto [x,y] = q.front();
q.pop();
for (int i=0;i<4;i++) {
int nx = x + dx[i];
int ny = y + dy[i];
if (nx<0 || nx>=n || ny<0 || ny>=n) continue;
if (grid[nx][ny]=='T') continue;
if (grid[nx][ny]=='D') continue;
if (dist[nx][ny]==-1) {
dist[nx][ny]=dist[x][y]+1;
q.push({nx,ny});
}
}
}
// for (int i=0;i<n;i++) {
// for (int j=0;j<n;j++) {
// cout<<dist[i][j]<<" ";
// }
// cout<<"\n";
// }
// cout<<"\n";
if (!bfs(0)) {
cout<<-1<<"\n";
return 0;
}
int left=0,right=1000*1000;
while (left<right) {
int mid = left+(right-left+1)/2;
if (bfs(mid)) left=mid;
else right=mid-1;
}
cout<<left<<"\n";
}
