#include <iostream>
#include <cstdio>
#include <vector>
#include <utility>
#include <cmath>
#include <algorithm>
#include <array>
#include <set>
#include <climits>
#include <map>
#include <memory>
#include <string>
#include <deque>
using namespace std;
#define input "mecho.in"
#define output "mecho.out"
#define int long long
int n, s;
int ans=-1; //will be maxed during the binary search
vector<vector<int>> bees_reach;
deque<pair<int, int>> bees_bfs; //r, c start off while taking input
vector<string> a;//input field
vector<vector<int>> reach_copy;
deque<pair<int, int>> bfs_copy;
vector<pair<int, int>> dirs = {
{1, 0},
{-1, 0},
{0, 1},
{0, -1}
};
bool check(int m) {
vector<vector<int>> mecho_reach = reach_copy;
deque<pair<int, int>> mecho_bfs = bfs_copy;
if (bees_reach[mecho_bfs.front().first][mecho_bfs.front().second]<=(m*s)) return 0;
//do bfs with mecho's location except mech can never go to a tile with bees there less than or equal to (m*s)+steps
while (!mecho_bfs.empty()) {
pair<int, int> curr=mecho_bfs.front();
mecho_bfs.pop_front();
int r=curr.first, c=curr.second;
int curr_steps=mecho_reach[r][c];
//cout << "r " << r << " c " << c << " curr_steps " << curr_steps << endl;
if (a[r][c]=='D') {
return 1;
}
for (pair<int, int> dir: dirs) {
int new_r=r+dir.first, new_c=c+dir.second;
if (new_r<0 || new_r>=n || new_c<0 || new_c>=n || a[new_r][new_c]=='T' || mecho_reach[new_r][new_c]!=-1) continue;
if (bees_reach[new_r][new_c]<=(m*s)+curr_steps+1 && bees_reach[new_r][new_c]!=-1) continue;
mecho_reach[new_r][new_c]=curr_steps+1;
mecho_bfs.push_back({new_r, new_c});
}
}
return 0;
}
signed main() {
ios_base::sync_with_stdio(0); cin.tie(0);
//freopen(input, "r", stdin);
//freopen(output, "w", stdout);
cin >> n >> s;
bees_reach.resize(n, vector<int>(n, -1));
reach_copy.resize(n, vector<int>(n, -1));
a.reserve(n);
for (int r=0;r<n;r++) {
string s; cin >> s;
a.push_back(s);
for (int c=0;c<n;c++) {
if (a[r][c]=='H') {
bees_bfs.push_back({r, c});
bees_reach[r][c]=0;
}
else if (a[r][c]=='M') {
bfs_copy.push_back({r, c});
reach_copy[r][c]=0;
}
}
}
while (!bees_bfs.empty()) {
pair<int, int> curr=bees_bfs.front();
bees_bfs.pop_front();
int r=curr.first, c=curr.second; int curr_steps=bees_reach[r][c];
for (pair<int, int> dir: dirs) {
int new_r=r+dir.first, new_c=c+dir.second;
if (new_r<0 || new_r>=n || new_c<0 || new_c>=n || a[new_r][new_c]=='T' || a[new_r][new_c]=='D') continue;
if (bees_reach[new_r][new_c]==-1) {
bees_reach[new_r][new_c]=curr_steps+s;
bees_bfs.push_back({new_r, new_c});
}
}
}
int l=0, r=1000*1000;
while (l<=r) {
int m=(l+r)/2;
//cout << m << endl;
if (check(m)) {
ans=m;
l=m+1;
}
else {
r=m-1;
}
}
cout << ans << endl;
}
