#include<bits/stdc++.h>
using namespace std;
const int N = 805, inf = 1e9;
string a[N];
int d[N][N], dis[N][N], n, s;
bool vis[N][N];
pair<int, int> st, en;
int mx = 0;
int movex[] = {1, 0, -1, 0};
int movey[] = {0, 1, 0, -1};
vector<pair<int, int>> allhives;
void fill(){
for(int i = 0; i < 801; i++){
for(int j = 0; j < 801; j++){
d[i][j] = inf;
}
}
}
bool check(int i, int j, bool which){
if(which == 1)
{
if(i >= 0 && i < n && j >= 0 && j < n && (a[i][j] == 'G' || a[i][j] == 'D') && !vis[i][j]){
return 1;
}
return 0;
}
else{
if(i >= 0 && i < n && j >= 0 && j < n && a[i][j] == 'G' && !vis[i][j]){
return 1;
}
return 0;
}
}
void bfs(){
queue<pair<int, int>> q;
for(auto x : allhives){
q.push(x);
d[x.first][x.second] = 0;
}
while(!q.empty()){
pair<int, int> u = q.front(); q.pop();
for(int i1 = 0; i1 < 4; i1++){
int x = movex[i1], y = movey[i1];
if(d[u.first + x][u.second + y] != inf)continue;
if(check(u.first + x, u.second + y, 0)){
d[u.first + x][u.second + y] = d[u.first][u.second] + 1;
q.push({u.first + x, u.second + y});
mx = max(mx, d[u.first + x][u.second + y]);
}
}
}
}
bool possible(int x){
int cur = x + 1;
memset(vis, 0, sizeof vis);
queue<pair<pair<int, int>, pair<int,int>>> q;
q.push({{st.first, st.second}, {cur, s}});
vis[st.first][st.second] = 1;
while(!q.empty()){
auto k = q.front(); q.pop();
int u = k.first.first, v = k.first.second, chargesleft = k.second.second;
int now = k.second.first;
for(int i = 0; i < 4; i++){
if(check(u + movex[i], v + movey[i], 1)){
if(d[u + movex[i]][v + movey[i]] >= now){
if(chargesleft > 1){
q.push({{u + movex[i], v + movey[i]}, {now, chargesleft - 1}});
}else{
q.push({{u + movex[i], v + movey[i]}, {now + 1, s}});
}
vis[u + movex[i]][v + movey[i]] = 1;
}
}
}
}
/*cout << "x : " << x << '\n';
for(int i = 0; i < n; i++){
for(int j = 0; j < n; j++){
cout << vis[i][j];
}
cout << '\n';
}*/
if(vis[en.first][en.second])return 1;
return 0;
}
int main(){
cin >> n >> s;
fill();
for(int i = 0; i < n; i++){
cin >> a[i];
}
for(int i = 0; i < n; i++){
for(int j = 0; j < n; j++){
if(a[i][j] == 'H'){
allhives.push_back({i, j});
}
if(a[i][j] == 'M'){
st.first = i;
st.second = j;
}
if(a[i][j] == 'D'){
en.first = i;
en.second = j;
}
}
}
/*for(int i = 0; i < n; i++){
for(int j = 0; j < n; j++){
if(d[i][j] != inf)cout << d[i][j];
else cout << 0;
}
cout << '\n';
}*/
bfs();
int l = 0, r = mx;
int ans = -1;
while(l <= r){
int mid = l + (r - l + 1) / 2;
if(possible(mid)){
l = mid + 1;
ans = mid;
}else{
r = mid - 1;
}
}
cout << ans << '\n';
}
