#include <bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define FOR(i,a,b) for (auto i = (a); i <= (b); ++i)
#define NFOR(i,a,b) for(auto i = (a); i >= (b); --i)
#define all(x) (x).begin(), (x).end()
#define sz(x) int(x.size())
#define mp(i,a) make_pair(i,a)
#define pb(a) push_back(a)
typedef long long int lli;
typedef pair <int, int> df;
typedef vector <int> vi;
int te,n,s;pair<int,int> pob,poh;
char grid[800][800];
int tobc[800][800];
int visited[800][800];
pair<int,int> movearr[] = {{0,-1},{1,0},{0,1},{-1,0}};
int canmove(const pair<int,int>& pos, const pair<int,int>& ptom, const int& bearob)
{
if(ptom.S>=n||ptom.S<0||ptom.F>=n||ptom.F<0||grid[ptom.F][ptom.S]=='T')
return(0);
if(bearob==0&&grid[ptom.F][ptom.S]=='D')
return(0);
return(1);
}
int check(int t,int r)
{
if(tobc[pob.F][pob.S] <= t) return 0;
memset(visited, 0, sizeof(visited));
int maccom=0,step=0;
queue<pair<int,int>> sp1,sp2;
sp1.push(pob);
visited[pob.F][pob.S]=1;
while(sp1.size()!=0)
{
pair<int,int> pos=sp1.front();
for(int i=0;i<4;++i)
{
int x=pos.F+movearr[i].F,y=pos.S+movearr[i].S;
if(canmove(pos,{x, y},1) && !visited[x][y] )
{
if(tobc[x][y]>t&&(step!=s-1||tobc[x][y]!=t+1))
{
sp2.push({x,y});
visited[x][y]=1;
if(mp(x,y)==poh)
{
maccom++;
}
}
}
}
sp1.pop();
if(sp1.size()==0)
{
step = (1 + step)%s;
if(!step) ++t;
swap(sp1,sp2);
}
}
return(maccom);
}
void bfs1(vector<pair<int,int>> pos_vec)
{
memset(visited, 0, sizeof(visited));
queue<pair<int,int>> q;
for(uint i=0;i<pos_vec.size();++i)
{
q.push(pos_vec[i]);
visited[pos_vec[i].F][pos_vec[i].S]=1;
}
while(q.size())
{
pair<int,int> pos=q.front();
for(int i=0;i<4;++i)
{
int x=pos.F+movearr[i].F,y=pos.S+movearr[i].S;
if(canmove(pos,{x,y},0) && !visited[x][y])
{
q.push({x,y});
visited[x][y]=1;
tobc[x][y]=min(tobc[x][y],tobc[pos.F][pos.S]+1);
}
}
q.pop();
}
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
te=1;
cin>>n>>s;
vector<pair<int,int>> pobees;
for(int i=0;i<n;++i)
{
for(int i1=0;i1<n;++i1)
{
tobc[i][i1]=650000;
cin>>grid[i][i1];
if(grid[i][i1]=='M')
pob={i,i1};
else if(grid[i][i1]=='D')
poh={i,i1};
else if(grid[i][i1]=='H')
{
pobees.pb(mp(i,i1));
tobc[i][i1]=0;
}
}
}
bfs1(pobees);
int r=n*n,l=0,ans=-1;
while(l<=r)
{
int mid=(l+r+1)/2;
if(check(mid,r))
{
ans=mid;
l=mid+1;
}
else
r=mid-1;
}
cout<<ans<<endl;
return 0;
}
