#ifdef LOCAL
#define _GLIBCXX_DEBUG
#endif
#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
#define sz(s) ((int)s.size())
#define all(v) begin(v), end(v)
typedef long double ld;
const int MOD = 1000000007;
#define ff first
#define ss second
const int inf = (int)1e9;
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
using pll = pair<ll, ll>;
// *-> KISS*
int solve() {
int n, s; cin >> n >> s;
vector<string> v(n);
for(int i = 0; i < n; ++i) cin >> v[i];
pll start;
vector<pll> bees;
for(int i = 0; i < n; ++i) {
for(int j = 0; j < n; ++j) {
if(v[i][j] == 'M') start = {i, j};
else if(v[i][j] == 'H') bees.push_back({i, j});
}
}
// Valid function for mecho
auto mvalid = [&](int i, int j) {
return i >= 0 && j >= 0 && i < n && j < n && v[i][j] != 'T';
};
// valid function for bees
auto bvalid = [&](int i, int j) {
return i >= 0 && j >= 0 && i < n && j < n && v[i][j] != 'T' && v[i][j] != 'D';
};
int dx[] = {-1, 0, 1, 0};
int dy[] = {0, 1, 0, -1};
int ans = -1;
int si = 0, ei = 10000;
while(si <= ei) {
int mid = (si + ei) >> 1;
// We are assuming that Mecho will stay at it's place for mid minutes and then start moving towards
// his home
vector<vector<bool>> bvis(n, vector<bool>(n, false)),
mvis(n, vector<bool>(n, false));
vector<pll> last;
vector<vector<int>> steps(n, vector<int>(n, inf));
{
queue<array<ll, 3>> q;
for(int i = 0; i < sz(bees); ++i) {
q.push({bees[i].ff, bees[i].ss, 0});
bvis[bees[i].ff][bees[i].ss] = true;
}
while(!q.empty()) {
array<ll, 3> t = q.front(); q.pop();
/* debug(t); */
steps[t[0]][t[1]] = 0;
if(t[2] == mid) {
last.push_back({t[0], t[1]});
continue;
}
int x = t[0], y = t[1], step = t[2];
for(int i = 0; i < 4; ++i) {
int ni = x + dx[i], nj = y + dy[i];
if(bvalid(ni, nj) && !bvis[ni][nj] && step + 1 <= mid) {
bvis[ni][nj] = true;
q.push({ni, nj, step + 1});
}
}
}
}
bool yes = false;
if(!bvis[start.ff][start.ss]) yes = true;
queue<array<ll, 3>> q;
for(int i = 0; i < sz(last); ++i) {
q.push({last[i].ff, last[i].ss, 0});
}
while(!q.empty()) {
array<ll, 3> _ = q.front(); q.pop();
/* debug(_); */
int x = _[0], y = _[1], step = _[2];
steps[x][y] = step * s;
for(int i = 0; i < 4; ++i) {
int ni = x + dx[i], nj = y + dy[i];
if(bvalid(ni, nj) && !bvis[ni][nj]) {
q.push({ni, nj, step + 1});
bvis[ni][nj] = true;
}
}
}
/* debug(steps); */
q = queue<array<ll, 3>> ();
/* debug(bvis); */
if(yes) q.push({start.ff, start.ss, 0});
/* if(!sz(q)) cout << mid << endl; */
mvis[start.ff][start.ss] = true;
ll minutes = -1; // -1 means unreachability
while(!q.empty()) {
array<ll, 3> t = q.front(); q.pop();
int x = t[0], y = t[1], step = t[2];
if(v[x][y] == 'D') {
minutes = step;
break;
}
for(int i = 0; i < 4; ++i) {
int ni = x + dx[i], nj = y + dy[i];
if(mvalid(ni, nj) && !mvis[ni][nj] && steps[ni][nj] > (step + 1)) {
mvis[ni][nj] = true;
q.push({ni, nj, step + 1});
}
}
}
if(minutes != -1) {
ans = mid; si = mid + 1;
}
else ei = mid - 1;
}
cout << ans;
return 0;
}
int32_t main() {
ios::sync_with_stdio(0);
cin.tie(0);
bool test = false;
int TET = 1;
if(test) cin >> TET;
cout << fixed << setprecision(6);
for (int i = 1; i <= TET; i++) {
#ifdef LOCAL
cout << "##################" << '\n';
#endif
if (solve()) {
break;
}
cout << '\n';
}
#ifdef LOCAL
cout << endl << "finished in " << clock() * 1.0 / CLOCKS_PER_SEC << " sec" << endl;
#endif
return 0;
}
// -> Keep It Simple Stupid!
