#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include <debug.h>
#else
#define debug(...)
#endif
#define ft front
#define bk back
#define st first
#define nd second
#define ins insert
#define ers erase
#define pb push_back
#define pf push_front
#define _pb pop_back
#define _pf pop_front
#define lb lower_bound
#define ub upper_bound
#define mtp make_tuple
#define bg begin
#define ed end
#define all(x) (x).bg(), (x).ed()
#define sz(x) (int)(x).size()
#define int long long
typedef long long ll; typedef unsigned long long ull;
typedef double db; typedef long double ldb;
typedef pair<int, int> pi; typedef pair<ll, ll> pll;
typedef vector<int> vi; typedef vector<ll> vll; typedef vector<pi> vpi; typedef vector<pll> vpll;
typedef string str;
template<typename T> T gcd(T a, T b) { return (b == 0? a : gcd(b, a % b)); }
template<typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }
#define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
#define FOS(i, r, l) for (int (i) = (r); (i) >= (l); --(i))
#define FRN(i, n) for (int (i) = 0; (i) < (n); ++(i))
#define FSN(i, n) for (int (i) = (n) - 1; (i) >= 0; --(i))
#define EACH(i, x) for (auto &(i) : (x))
#define WHILE while
#define file "TEST"
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
ll rand(ll l, ll r) { return uniform_int_distribution<ll>(l, r)(rd); }
/*
----------------------------------------------------------------
END OF TEMPLATE
----------------------------------------------------------------
Tran The Bao - ghostwriter
Training for VOI23 gold medal
----------------------------------------------------------------
DIT ME CHUYEN BAO LOC
----------------------------------------------------------------
*/
const int N = 801;
const vpi dxy = {{0, -1}, {0, 1}, {-1, 0}, {1, 0}};
int n, s, d[N][N], d1[N][N];
char a[N][N], a1[N][N];
bool check(int tm) {
FOR(i, 1, n)
FOR(j, 1, n)
a1[i][j] = a[i][j];
vpi index;
pi home;
FOR(i, 1, n)
FOR(j, 1, n)
if (a[i][j] == 'H')
index.pb({i, j});
FOR(i, 1, tm) {
vpi index1;
EACH(j, index) {
int x = j.st, y = j.nd;
EACH(z, dxy) {
int x1 = x + z.st, y1 = y + z.nd;
if (x1 < 1 || x1 > n || y1 < 1 || y1 > n) continue;
if (a1[x1][y1] != 'H' && a1[x1][y1] != 'D' && a1[x1][y1] != 'T') {
a1[x1][y1] = 'H';
index1.pb({x1, y1});
}
}
}
swap(index, index1);
}
pi ph = {0, 0}, ps = {0, 0};
FOR(i, 1, n)
FOR(j, 1, n)
if (a1[i][j] == 'D') ph = {i, j};
else if (a1[i][j] == 'M') ps = {i, j};
if (!ph.st || !ps.st) return 0;
memset(d, -1, sizeof d);
queue<pi> q;
FOR(i, 1, n)
FOR(j, 1, n)
if (a1[i][j] == 'H') {
d[i][j] = 0;
q.push({i, j});
}
WHILE(!q.empty()) {
int x = q.ft().st, y = q.ft().nd;
q.pop();
EACH(i, dxy) {
int x1 = x + i.st, y1 = y + i.nd;
if (x1 < 1 || x1 > n || y1 < 1 || y1 > n || a1[x1][y1] == 'T' || a1[x1][y1] == 'D' || d[x1][y1] != -1) continue;
d[x1][y1] = d[x][y] + 1;
q.push({x1, y1});
}
}
memset(d1, -1, sizeof d1);
d1[ps.st][ps.nd] = 0;
q.push(ps);
WHILE(!q.empty()) {
int x = q.ft().st, y = q.ft().nd;
q.pop();
EACH(i, dxy) {
int x1 = x + i.st, y1 = y + i.nd;
if (x1 < 1 || x1 > n || y1 < 1 || y1 > n || a1[x1][y1] == 'T' || d1[x1][y1] != -1 || (d[x1][y1] != -1 && (d1[x][y] + 1) / s >= d[x1][y1])) continue;
d1[x1][y1] = d1[x][y] + 1;
q.push({x1, y1});
}
}
return d1[ph.st][ph.nd] != -1? 1 : 0;
}
signed main() {
ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
// freopen(file".inp", "r", stdin);
// freopen(file".out", "w", stdout);
cin >> n >> s;
FOR(i, 1, n)
FOR(j, 1, n)
cin >> a[i][j];
int l = 0, r = n * n, ans = -1;
WHILE(l <= r) {
int mid = l + (r - l) / 2;
if (check(mid)) {
ans = mid;
l = mid + 1;
}
else r = mid - 1;
}
cout << ans;
return 0;
}
/*
7 3
TTTTTTT
TGGGGGT
TGGGGGT
MGGGGGD
TGGGGGT
TGGGGGT
THHHHHT
----------------------------------------------------------------
From Benq:
stuff you should look for
* int overflow, array bounds
* special cases (n=1?)
* do smth instead of nothing and stay organized
* WRITE STUFF DOWN
* DON'T GET STUCK ON ONE APPROACH
----------------------------------------------------------------
*/
