#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
#define ll long long
#define int long long int
#define pii pair<int,int>
#define vi vector<int>
#define vvi vector<vector<int>>
#define all(x) begin(x),end(x)
#define rev(x) rbegin(x),rend(x)
#define min_priority_queue(x) priority_queue<x, vector<x>,greater<x>>
const int MOD = 1000000007;
const int INF = 1e18;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
void arrin(vi&x,int n){ for(int i=0;i<n;i++){cin >> x[i];}}
void arrout(vi&x){ for(int i=0;i<x.size();i++){cout<< x[i]<<" ";}cout<< endl;}
void pr_bool(bool i){ cout << (i ? "YES" : "NO") << endl;}
int gcd(int a,int b){ if(b==0) return a; return gcd(b, a%b);}
int lcm(int a,int b){ return a/gcd(a,b)*b;}
bool bfs2(int si,int sj,vvi& dist,vector<string>& x,int s,pii des,int m){
int n = x.size();
vvi dist2(n,vi(n,-1));
queue<array<int,4>> q;
q.push({si,sj,m,0});
while(!q.empty()){
int sz=q.size();
while(sz--){
auto [i,j,dis,cnt]=q.front();
q.pop();
int dx[4]={1,-1,0,0}, dy[4]={0,0,1,-1};
for(int k=0;k<4;k++){
int ni=i+dx[k], nj=j+dy[k];
if(ni<0||nj<0||ni>=n||nj>=n||x[ni][nj]=='T') continue;
int newDis = dis, newCnt = cnt+1;
if(newCnt == s){
newDis++;
newCnt = 0;
}
if(dist[ni][nj] - newDis > dist2[ni][nj]){
dist2[ni][nj] = dist[ni][nj] - newDis;
q.push({ni,nj,newDis,newCnt});
}
}
}
}
return dist2[des.first][des.second] != -1;
}
int32_t main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL); cout.tie(NULL);
int n,s; cin >> n >> s;
vector<string> x(n);
pii st,des,hive;
for(int i = 0;i < n;i++){
cin >> x[i];
}
queue<pair<pii,int>> hives;
vvi dist(n,vi(n,-1));
for(int i = 0;i < n;i++){
for(int j = 0;j < n;j++){
if(x[i][j] == 'H'){
dist[i][j] = 0;
hives.push({{i,j},0});
}
if(x[i][j] == 'M') st = {i,j};
if(x[i][j] == 'D') des = {i,j};
}
}
vvi dir = {{-1,0},{1,0},{0,1},{0,-1}};
while(hives.size()){
int i = hives.front().first.first,j = hives.front().first.second,dis = hives.front().second;
hives.pop();
for(auto&u : dir){
int nx = i + u[0],ny = j + u[1];
if(nx < 0 || ny < 0 || nx >= n || ny >= n || x[nx][ny] == 'T' || dist[nx][ny] != -1) continue;
dist[nx][ny] = dis + 1;
hives.push({{nx,ny},dis+1});
}
}
// for(int i = 0;i < n;i++){
// arrout(dist[i]);
// }
int ans = -1;
int l = 0,r = dist[des.first][des.second];
while(l <= r){
int m = (l+r)/2;
if(bfs2(st.first,st.second,dist,x,s,des,m)){
ans = m;
l = m+1;
}
else{
r = m-1;
}
}
if(ans == -1) ans = 0;
cout << ans-1 << endl;
}
// 07:30:10
