#include <bits/stdc++.h>
using namespace std;
struct node{
int i;
int j;
node(){}
node(int I,int J){
i=I;
j=J;
}
};
queue<node> Q;
char forest[805][805];
int bees[805][805];
int dist[805][805];
int energy[805][805];
int dx[4]={1,-1,0,0};
int dy[4]={0,0,1,-1};
int n,s;
void bfsBees(){ for (int i = 1; i <= n; i++){ for (int j = 1; j <= n; j++){ bees[i][j]=INT_MAX;
if(forest[i][j]=='H'){
Q.push(node(i,j));
bees[i][j]=0; } } }
while(!Q.empty()){
node u=Q.front();
Q.pop();
for(int mov=0;mov<4;mov++){
int i=u.i+dx[mov];
int j=u.j+dy[mov];
if(i<1 || i>n) continue;
if(j<1 || j>n) continue;
if(forest[i][j]=='T' || forest[i][j]=='D') continue;
if(bees[i][j]==INT_MAX){
bees[i][j]=bees[u.i][u.j]+1;
Q.push(node(i,j));
}
}
}
}
node mecho;
node home;
bool bfsMecho(int init){ for (int i = 1; i <= n; i++){ for (int j = 1; j <= n; j++){ dist[i][j]=INT_MAX;
energy[i][j]=0; }}
if(bees[mecho.i][mecho.j]<=init) return false;
dist[mecho.i][mecho.j]=init;
energy[mecho.i][mecho.j]=0;
Q.push(mecho);
while(!Q.empty()){
node u=Q.front();
Q.pop();
if(bees[u.i][u.j]==dist[u.i][u.j] && energy[u.i][u.j]==0) continue;
for(int mov=0;mov<4;mov++){
int i=u.i+dx[mov];
int j=u.j+dy[mov];
if(i<1 || i>n) continue;
if(j<1 || j>n) continue;
if(forest[i][j]=='T') continue;
if(dist[i][j]==INT_MAX){
int change=(energy[u.i][u.j]>0)? 0 : 1;
dist[i][j]=dist[u.i][u.j]+change;
if(bees[i][j]<dist[i][j]) continue;
energy[i][j]=(energy[u.i][u.j]>0)? energy[u.i][u.j]-1 : s-1;
Q.push(node(i,j));
}
}
}
return dist[home.i][home.j]!=INT_MAX;
}
int binarySearch(){
int k=-1;
int L=0,R=3*n;
while(L<R){
int mid=(L+R)/2;
if(bfsMecho(mid)){
k=mid;
L=mid+1;
}
else{
R=mid;
}
}
return k;
}
int binarySearch2(){
int k=-1;
for(int b=5000;b>=1;b/=2){
while(bfsMecho(b+k)) k+=b;
}
return k;
}
int main()
{
ios_base::sync_with_stdio(0);cin.tie(0);
cin>>n>>s;
for(int i=1;i<=n;i++){
for(int j=1;j<=n;j++){
cin>>forest[i][j];
if(forest[i][j]=='M'){
mecho=node(i,j);
}
else if(forest[i][j]=='D'){
home=node(i,j);
}
}
}
bfsBees();
int ans=binarySearch2();
cout<<ans<<endl;
return 0;
}
