#include <bits/stdc++.h> //Andrei Alexandru a.k.a Sho
#define ll long long
#define double long double
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#define aint(a) (a).begin(), (a).end()
#define f first
#define s second
#define pb push_back
#define mp make_pair
#define pi pair
#define rc(s) return cout<<s,0
#define endl '\n'
#define mod 998244353
#define PI 3.14159265359
#define INF 1000000005
#define LINF 1000000000000000005ll
#define CODE_START ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
using namespace std;
ll n,s,sx,sy,dbees[805][805],d[805][805],viz[805][805],fx,fy;
pair<ll,ll>direction[5];
char a[805][805];
vector<pair<ll,ll>>hive;
ll check(ll x,ll y){
if(x>=1&&y>=1&&x<=n&&y<=n){
return 1;
}else return 0;
}
ll verif(ll time){
for(ll i=1;i<=n;i++)
for(ll j=1;j<=n;j++)
{
d[i][j]=LINF;
viz[i][j]=0;
}
queue<pair<ll,ll>>q;
d[sx][sy]=0;
viz[sx][sy]=1;
q.push(mp(sx,sy));
if(dbees[sx][sy]<=time){
q.pop();
}
while(!q.empty()){
ll x,y;
x=q.front().f;
y=q.front().s;
//cout<<x<<' '<<y<<endl;
q.pop();
for(ll i=0;i<4;i++)
{
ll xx,yy;
xx=x+direction[i].f;
yy=y+direction[i].s;
if(a[xx][yy]=='T'||a[xx][yy]=='H'){
continue;
}
if(check(xx,yy)==0){
continue;
}
if(viz[xx][yy]==1){
continue;
}
if((d[x][y]+1)/s>=dbees[xx][yy]-time){
continue;
}
viz[xx][yy]=1;
d[xx][yy]=d[x][y]+1;
q.push(mp(xx,yy));
}
}
ll ans=0;
for(ll i=0;i<4;i++)
{
ll x=fx+direction[i].f,y=fy+direction[i].s;
if(check(x,y)==0){
continue;
}
if(viz[x][y]==0){
continue;
}
if((d[x][y]/s)<dbees[x][y]-time){
ans=1;
}
}
return ans;
}
int32_t main(){
//CODE_START;
//ifstream cin("input.in");
direction[0]=mp(-1,0);
direction[1]=mp(1,0);
direction[2]=mp(0,-1);
direction[3]=mp(0,1);
cin>>n>>s;
for(ll i=1;i<=n;i++)
{
for(ll j=1;j<=n;j++)
{
cin>>a[i][j];
if(a[i][j]=='M'){
sx=i;
sy=j;
}else if(a[i][j]=='H'){
hive.pb(mp(i,j));
}else if(a[i][j]=='D'){
fx=i;
fy=j;
}
}
}
for(ll i=1;i<=n;i++)
{
for(ll j=1;j<=n;j++)
{
dbees[i][j]=LINF;
}
}
queue<pair<ll,ll>>q;
for(auto it : hive){
q.push(it);
dbees[it.f][it.s]=0;
}
while(!q.empty()){
ll x,y;
x=q.front().f;
y=q.front().s;
q.pop();
for(ll i=0;i<4;i++)
{
ll xx,yy;
xx=x+direction[i].f;
yy=y+direction[i].s;
if(a[xx][yy]=='T'||a[xx][yy]=='D'||a[xx][yy]=='H'){
continue;
}
if(check(xx,yy)&&viz[xx][yy]==0){
viz[xx][yy]=1;
q.push(mp(xx,yy));
dbees[xx][yy]=dbees[x][y]+1;
}
}
}
ll l=0,r=n*n,ans=-1;
//cout<<"DA"<<endl;
while(l<=r){
ll mid=(l+r)/2;
// cout<<mid<<endl;
if(verif(mid)){
l=mid+1;
ans=mid;
}else {
r=mid-1;
}
}
cout<<ans<<endl;
}
