#include <bits/stdc++.h>
using namespace std;
const int MAX=810;
const int INF=(1<<30);
int di[4]={0,0,-1,1};
int dj[4]={1,-1,0,0};
int n,s;
char mat[MAX][MAX];
int timebees[MAX][MAX];
int beartime[MAX][MAX];
bool visbees[MAX][MAX];
bool visbear[MAX][MAX];
vector<pair<int,int> > hiveinitial;
vector<pair<int,int> > homeinitial;
int mi,mj;
int homei,homej;
bool valid_move(int i, int j)
{
if(i<0 || i>n || j<0 || j>n || mat[i][j]=='T' || mat[i][j]=='H' || mat[i][j]=='D')return false;
return true;
}
bool bearReach(int a, int b)
{
return a/s<b;
}
void bfsBees()
{
queue<pair<int,int> > q;
for(int i=0; i<hiveinitial.size(); i++)
{
int x=hiveinitial[i].first;
int y=hiveinitial[i].second;
visbees[x][y]=true;
timebees[x][y]=0;
q.push({x,y});
}
while(!q.empty())
{
pair<int,int> curr=q.front();
int x=curr.first;
int y=curr.second;
q.pop();
for(int k=0; k<4; k++)
{
int newi=x+di[k];
int newj=y+dj[k];
if(valid_move(newi,newj)&& !visbees[newi][newj])
{
visbees[newi][newj]=true;
q.push({newi,newj});
timebees[newi][newj]=timebees[x][y]+1;
}
}
}
return;
}
bool bfsBear(int eatTime)
{
queue<pair<int,int> > q;
q.push({mi,mj});
visbear[mi][mj]=true;
if(eatTime>=timebees[mi][mj])return false;
while(!q.empty())
{
pair<int,int> curr=q.front();
q.pop();
int x=curr.first;
int y=curr.second;
for(int k=0; k<4; k++)
{
int newi=di[k]+x;
int newj=dj[k]+y;
if(valid_move(newi,newj) && !visbear[newi][newj]&& bearReach(beartime[x][y]+1,timebees[newi][newj]-eatTime))
{
visbear[newi][newj]=true;
q.push({newi,newj});
beartime[newi][newj]=beartime[x][y]+1;
}
}
}
for(int k=0; k<4; k++)
{
int newi=homei+di[k];
int newj=homej+dj[k];
if(valid_move(newi,newj) && bearReach(beartime[newi][newj],timebees[newi][newj]-eatTime) && visbear[newi][newj])return true;
}
return false;
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
cin>>n>>s;
memset(beartime,0,sizeof(beartime));
for(int i=0; i<n; i++)
{
for(int j=0; j<n; j++)
{
cin>>mat[i][j];
if(mat[i][j]=='H')
{
hiveinitial.push_back({i,j});
}
if(mat[i][j]=='M')
{
mi=i;
mj=j;
}
if(mat[i][j]=='D')
{
homei=i;
homej=j;
}
}
}
bfsBees();
int b=0;
int e=n*n;
while(b<=e)
{
int mid=(b+e)/2;
if(bfsBear(mid))
{
b=mid+1;
}
else
{
e=mid-1;
}
}
cout<<b-1<<endl;
return 0;
}
