#include <bits/stdc++.h>
using namespace std;
#define LIFESUCKS ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define ll long long
#define ld long double
#define ar array
#include<cstdio>
#define vt vector
#include<fstream>
ifstream fin("piggyback.in");
ofstream fout("piggyback.out");
#include<fstream>
#define pb push_back
#define all(c) (c).begin(), (c).end()
#define fi first
#define se second
#define vt vector
using namespace std;
int n, s, sti, stj, eni, enj;
bool vis[801][801];
int dis[801][801];
int dis2[801][801];
char a[801][801];
bool bee = true;
const int x[4] = {1, -1, 0, 0};
const int y[4] = {0, 0, 1, -1};
bool check(int mid){
memset(vis, false, sizeof(vis));
memset(dis2, false, sizeof(dis2));
queue<pair<int, int>>q;
q.push({sti, stj});
vis[sti][stj] = true;
if(mid >= dis[sti][stj])return(false);
dis2[sti][stj] = 0;
while(!q.empty()){
auto now = q.front(); q.pop();
//cout << "mm";
for(int i = 0; i < 4; i++){
int cri = now.fi + x[i];
int crj = now.se + y[i];
if(cri < 0 || crj < 0 || cri >= n || crj >= n)continue;
if(!vis[cri][crj] &&(a[cri][crj] == 'G' || a[cri][crj] == 'D' || a[cri][crj] == 'M')){
// cout << "lol";
if(dis[cri][crj] > floor((double)(dis2[now.fi][now.se] + 1) / (double)s) + mid){
vis[cri][crj] = true;
dis2[cri][crj] = dis2[now.fi][now.se] + 1;
if(a[cri][crj] == 'D')return(true);
q.push({cri, crj});
}
}
}
}
//cout << "\n";
return(false);
}
void bfs(){
memset(vis, false, sizeof(vis));
queue<pair<int, int>>q;
for(int i = 0; i < n; i++){
for(int j = 0; j < n; j++){
if(a[i][j] == 'H'){
q.push({i, j});
vis[i][j] = true;
dis[i][j] = 0;
}
}
}
while(!q.empty()){
auto now = q.front(); q.pop();
for(int i = 0; i < 4; i++){
int cri = now.fi + x[i];
int crj = now.se + y[i];
if(cri < 0 || crj < 0 || cri >= n || crj >= n)continue;
if(!vis[cri][crj] && (a[cri][crj] == 'G' || a[cri][crj] == 'H' || a[cri][crj] == 'M')){
vis[cri][crj] = true;
dis[cri][crj] = dis[now.fi][now.se] + 1;
q.push({cri, crj});
}
}
}
}
int main(){
LIFESUCKS;
cin >> n >> s;
for(int i = 0; i < n; i++){
for(int j = 0; j < n; j++){
dis[i][j] = 1e9;
cin >> a[i][j];
if(a[i][j] == 'M'){
sti = i, stj = j;
}if(a[i][j] == 'D'){
eni = i; enj = j;
}
}
}
//cout << sti << ' ' << stj << " ";
bfs();
int l = 0;
int r = 1e9;
int ans = -1;
while(l <= r){
int mid = l + (r - l) / 2;
if(check(mid)){
ans = mid; l = mid + 1;
}else{
r = mid - 1;
}
}
cout << ans;
return 0;
}
