#include <bits/stdc++.h>
#define pb push_back
#define jizz ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define ET cout << "\n"
#define F first
#define S second
#define MP make_pair
#define ALL(v) v.begin(),v.end()
#define MEM memset(i,j,sizeof i)
#define DB(a,s,e) {for(int i=s;i<e;++i) cout << a[i] << " ";ET;}
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
const int INF=1e9;
int dx[4]={0,0,1,-1},dy[4]={1,-1,0,0},n,s;
string mp[805];
int ti[805][805],vis[805][805];
queue<pii> q;
pii st;
bool check(int x,int y)
{
return !(x<0||y<0||x>=n||y>=n||vis[x][y]||mp[x][y]=='T');
}
bool check2(int x,int y)
{
return !(x<0||y<0||x>=n||y>=n||vis[x][y]!=INF||mp[x][y]=='T');
}
int tran(int nw,int beg)
{
if(nw==beg) return beg;
return (nw-beg-1)/s+beg+1;
}
bool running(int m)
{
queue<pii> q;
for(int i=0;i<n;++i)
fill(vis[i],vis[i]+n,INF);
for(q.push(MP(st.F,st.S)),vis[st.F][st.S]=m;!q.empty();)
{
auto t=q.front();
q.pop();
if(tran(vis[t.F][t.S],m)>ti[t.F][t.S]) continue;
if(tran(vis[t.F][t.S],m)==ti[t.F][t.S]&&(vis[t.F][t.S]-m)%s==0) continue;
if(mp[t.F][t.S]=='D') return 1;
for(int i=0;i<4;++i)
if(check2(t.F+dx[i],t.S+dy[i]))
q.push(MP(t.F+dx[i],t.S+dy[i])),vis[t.F+dx[i]][t.S+dy[i]]=vis[t.F][t.S]+1;
}
return 0;
}
int main()
{jizz
int l=-1,r;
cin >> n >> s;
for(int i=0;i<n;++i)
cin >> mp[i];
for(int i=0;i<n;++i)
for(int j=0;j<n;++j)
ti[i][j]=INF;
for(int i=0;i<n;++i)
for(int j=0;j<n;++j)
if(mp[i][j]=='H')
q.push(MP(i,j)),vis[i][j]=1,ti[i][j]=0;
else if(mp[i][j]=='T'||mp[i][j]=='D')
vis[i][j]=1;
else if(mp[i][j]=='M')
st=MP(i,j);
while(!q.empty())
{
auto t=q.front();
q.pop();
for(int i=0;i<4;++i)
if(check(t.F+dx[i],t.S+dy[i]))
q.push(MP(t.F+dx[i],t.S+dy[i])),vis[t.F+dx[i]][t.S+dy[i]]=1,ti[t.F+dx[i]][t.S+dy[i]]=ti[t.F][t.S]+1;
}
for(r=ti[st.F][st.S];r-l>1;)
{
int m=(l+r)/2;
if(running(m)) l=m;
else r=m;
}
cout << l << "\n";
}
