#include<bits/stdc++.h>
using namespace std;
int dx[]={-1,1,0,0};
int dy[]={0,0,-1,1};
const int INF=1e9;
int F[888][888],G[888][888];
string s[888];
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n,k;
cin>>n>>k;
int x1,y1,x2,y2;
queue< pair<int,int> > Q;
for(int i=1;i<=n;i++) for(int j=1;j<=n;j++) F[i][j]=INF;
for(int i=1;i<=n;i++)
{
cin>>s[i];
s[i]=' '+s[i];
for(int j=1;j<=n;j++) if(s[i][j]=='H') F[i][j]=0,Q.push({i,j});
else if(s[i][j]=='M') x1=i,y1=j;
else if(s[i][j]=='D') x2=i,y2=j;
}
while(!Q.empty())
{
int a=Q.front().first,b=Q.front().second;
Q.pop();
for(int i=0;i<4;i++)
{
int x=a+dx[i],y=b+dy[i];
if(min(x,y)>=1&&max(x,y)<=n&&s[x][y]!='T'&&s[x][y]!='D'&&F[x][y]==INF) F[x][y]=F[a][b]+1,Q.push({x,y});
}
}
int l=0,r=F[x1][y1]-1,ans=-1;
while(l<=r)
{
int mid=(l+r)/2;
for(int i=1;i<=n;i++) for(int j=1;j<=n;j++) G[i][j]=INF;
G[x1][y1]=mid*k,Q.push({x1,y1});
while(!Q.empty())
{
int a=Q.front().first,b=Q.front().second;
Q.pop();
if(G[a][b]/k>=F[a][b]) continue;
for(int i=0;i<4;i++)
{
int x=a+dx[i],y=b+dy[i];
if(min(x,y)>=1&&max(x,y)<=n&&s[x][y]!='T'&&G[x][y]==INF) G[x][y]=G[a][b]+1,Q.push({x,y});
}
}
if(G[x2][y2]!=INF) l=mid+1,ans=mid;
else r=mid-1;
}
cout<<ans;
}
