// EXPLOSION!
#define _CRT_SECURE_NO_WARNINGS
#include<bits/stdc++.h>
#include<unordered_set>
#include<unordered_map>
#include<chrono>
using namespace std;
typedef pair<int, int> pii;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<pair<int, int>> vpi;
typedef vector<pair<ll, ll>> vpll;
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define trav(a,x) for (auto& a: x)
#define pb push_back
#define mp make_pair
#define rsz resize
#define sz(x) int(x.size())
#define all(x) x.begin(),x.end()
#define f first
#define s second
#define cont continue
#define endl '\n'
//#define ednl '\n'
#define test int testc;cin>>testc;while(testc--)
#define pr(a, b) trav(x,a)cerr << x << b; cerr << endl;
#define message cout << "Hello World" << endl;
const int dx[4] = { 1,0,-1,0 }, dy[4] = { 0,1,0,-1 }; // for every grid problem!!
const ll linf = 4000000000000000000LL;
const ll inf = 1000000007;//998244353
void pv(vi a) { trav(x, a)cout << x << " "; cout << endl; }void pv(vll a) { trav(x, a)cout << x << " "; cout << endl; }void pv(vector<vi>a) {
F0R(i, sz(a)) { cout << i << endl; pv(a[i]); cout << endl; }
}void pv(vector<vll>a) { F0R(i, sz(a)) { cout << i << endl; pv(a[i]); }cout << endl; }void pv(vector<string>a) { trav(x, a)cout << x << endl; cout << endl; }
void setIO(string s) {
ios_base::sync_with_stdio(0); cin.tie(0);
if (sz(s))
{
freopen((s + ".in").c_str(), "r", stdin);
if (s != "test1")
freopen((s + ".out").c_str(), "w", stdout);
}
}
int n, m;
const int MAX = 805;
string a[MAX];
int dist[MAX][MAX];
int check(int i, int j)
{
return i >= 0 && j >= 0 && i < n&& j < n&& a[i][j] != 'T';
}
struct T
{
int d, extra;
T next()
{
T t = (*this);
t.extra--;
if (t.extra == 0)
{
t.extra = m;
t.d++;
}
return t;
}
bool operator<(const T& x)const
{
if (d == x.d)return extra > x.extra;
return d < x.d;
}
};
T best[MAX][MAX];
T init = { inf,0 };
pii start, finish;
int solve(int t)
{
F0R(i, n)F0R(j, n)best[i][j] = init;
if (t >= dist[start.f][start.s])return 0;
best[start.f][start.s] = { t,m };
deque<pii>todo = { {start.f,start.s} };
while (sz(todo))
{
int i = todo.back().f, j = todo.back().s;
todo.pop_back();
F0R(k, 4)
{
int x = i + dx[k], y = j + dy[k];
if (check(x, y))
{
T temp = best[i][j];
temp = temp.next();
if (dist[x][y] > temp.d && temp < best[x][y])
{
best[x][y] = temp;
todo.push_front({ x,y });
}
}
}
}
return best[finish.f][finish.s].d != inf;
}
int main()
{
setIO("");
cin >> n >> m;
F0R(i, n)cin >> a[i];
F0R(i, n)
{
F0R(j, n)
{
if (a[i][j] == 'M')start = { i,j };
if (a[i][j] == 'D')finish = { i,j };
}
}
F0R(i, n)F0R(j, n)dist[i][j] = inf;
deque<pii> todo;
F0R(i, n)F0R(j, n)if (a[i][j] == 'H')todo.pb({ i,j }), dist[i][j] = 0;
while (sz(todo))
{
int i = todo.back().f, j = todo.back().s;
todo.pop_back();
F0R(k, 4)
{
int x = i + dx[k], y = j + dy[k];
if (check(x, y) && a[x][y] != 'D' && dist[x][y] > dist[i][j] + 1)
{
dist[x][y] = dist[i][j] + 1;
todo.push_front({ x,y });
}
}
}
if (!solve(0))
{
cout << -1 << endl;
return 0;
}
int l = 0, r = 2 * n * n;
while (l < r)
{
int m = (l + r + 1) / 2;
if (solve(m))
{
l = m;
}
else
{
r = m - 1;
}
}
cout << l << endl;
}
