#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ld long double
#define show(x,y) cout << y << " " << #x << endl;
#define show2(x,y,i,j) cout << y << " " << #x << " " << j << " " << #i << endl;
#define show3(x,y,i,j,p,q) cout << y << " " << #x << " " << j << " " << #i << " " << q << " " << #p << endl;
#define show4(x,y) for(auto it:x) cout << it << " "; cout << #y << endl;
typedef pair<int,int>pii;
typedef pair<pii,pii>pi2;
void solve(){
int n,k;
cin >> n >> k;
string arr[n];
for(int x=0;x<n;x++){
cin >> arr[x];
}
int l=0;
int r=n*n;
int best=-1;
int mid;
pii start;
pii done;
int dist[n+5][n+5];
memset(dist,-1,sizeof(dist));
queue<pii>q;
for(int x=0;x<n;x++){
for(int y=0;y<n;y++){
if(arr[x][y]=='H'){
q.push({x,y});
dist[x][y]=0;
}
else if(arr[x][y]=='M') start={x,y};
else if(arr[x][y]=='D') done={x,y};
}
}
pii dir[4]={
{0,1},
{0,-1},
{1,0},
{-1,0},
};
while(!q.empty()){
pii cur=q.front();
q.pop();
for(auto it:dir){
int newx=cur.first+it.first;
int newy=cur.second+it.second;
if(newx<0||newy<0||newx>=n||newy>=n) continue;
if(dist[newx][newy]!=-1) continue;
if(arr[newx][newy]=='G'||arr[newx][newy]=='M'){
dist[newx][newy]=dist[cur.first][cur.second]+1;
q.push({newx,newy});
}
}
}
while(l<=r){
mid=(l+r)/2;
int dist2[n][n];
memset(dist2,-1,sizeof(dist2));
dist2[start.first][start.second]=k*mid;
if(mid<dist[start.first][start.second])q.push({start.first,start.second});
bool visited[n+5][n+5];
memset(visited,0,sizeof(visited));
while(!q.empty()){
pii cur=q.front();
q.pop();;
for(auto it:dir){
int newx=cur.first+it.first;
int newy=cur.second+it.second;
if(newx<0||newy<0||newx>=n||newy>=n) continue;
if(dist2[newx][newy]!=-1) continue;
if(dist[newx][newy]<=(dist2[cur.first][cur.second]+1)/k) continue;
if(arr[newx][newy]=='M'||arr[newx][newy]=='G'){
dist2[newx][newy]=dist2[cur.first][cur.second]+1;
q.push({newx,newy});
}
}
}
bool amos=false;
for(auto it:dir){
int newx=done.first+it.first;
int newy=done.second+it.second;
if(newx<0||newy<0||newx>=n||newy>=n) continue;
if(dist2[newx][newy]==-1) continue;
if(dist[newx][newy]<=dist2[newx][newy]/k) continue;
if(arr[newx][newy]=='G'||arr[newx][newy]=='M'){
if(dist2[newx][newy]!=-1) amos=true;
}
}
if(amos){
best=mid;
l=mid+1;
}
else r=mid-1;
}
cout << best;
}
int32_t main(){
ios::sync_with_stdio(0);
cin.tie(0);
//freopen("out.txt", "w", stdout);
int t=1;
//cin >> t;
while(t--){
solve();
}
}
