#include <cstdio>
#include <iostream>
#include <algorithm>
#include <string>
#include <cstring>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <cmath>
#include <iomanip>
#include <cassert>
#include <bitset>
using namespace std;
typedef pair<int, int> P;
#define rep(i, n) for (int i=0; i<(n); i++)
#define all(c) (c).begin(), (c).end()
#define uniq(c) c.erase(unique(all(c)), (c).end())
#define index(xs, x) (int)(lower_bound(all(xs), x) - xs.begin())
#define _1 first
#define _2 second
#define pb push_back
#define INF 1145141919
#define MOD 1000000007
const int DX[4]={-1,0,1,0};
const int DY[4]={0,-1,0,1};
int N, S;
char A[800][800];
int T[800][800];
int dp[800][800];
bool f(int X) {
queue<P> q;
rep(x,N)rep(y,N)dp[x][y]=INF;
rep(y,N)rep(x,N)if(A[x][y]=='M'&&1LL*X*S<T[x][y])dp[x][y]=X*S,q.push(P(x,y));
while(!q.empty()){
int x=q.front()._1, y=q.front()._2;q.pop();
rep(k,4){
int nx=x+DX[k],ny=y+DY[k];
if(nx<0||nx>=N||ny<0||ny>=N||A[nx][ny]=='T'||dp[nx][ny]<=dp[x][y]+1) continue;
if (A[nx][ny]=='D')return true;
if (dp[x][y]+1>=T[nx][ny]) continue;
dp[nx][ny]=dp[x][y]+1;
q.push(P(nx,ny));
}
}
return false;
}
signed main() {
ios::sync_with_stdio(false); cin.tie(0);
cin >> N >> S;
rep(y,N)rep(x,N)cin>>A[x][y],T[x][y]=INF;
queue<P> q;
rep(x,N)rep(y,N)if(A[x][y]=='H') T[x][y]=0, q.push(P(x,y));
while(!q.empty()){
int x=q.front()._1, y=q.front()._2;q.pop();
rep(k,4){
int nx=x+DX[k],ny=y+DY[k];
if(nx<0||nx>=N||ny<0||ny>=N||A[nx][ny]=='T'||A[nx][ny]=='D'||T[nx][ny]!=INF) continue;
T[nx][ny]=T[x][y]+S;
q.push(P(nx,ny));
}
}
int lo=-1, hi=N*N+1;
while (hi-lo>1){
int mid=(lo+hi)/2;
if (f(mid)) lo = mid;
else hi=mid;
}
cout << lo << "\n";
return 0;
}
