#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int nx = 805;
int n; ll s;
char grid[nx][nx];
ll dist_bee[nx][nx];
int sy, sx, dy, dx;
int xx[4] = {-1, 0, 1, 0};
int yy[4] = {0, 1, 0, -1};
vector<pair<int,int>> hives;
// T, G, M, D, H
bool check(int time) {
queue<pair<int,int>> q;
bool vis[nx][nx]; memset(vis, 0, sizeof vis);
ll dist[nx][nx]; memset(dist, 0, sizeof dist);
dist[sy][sx] = s * time;
q.emplace(sy, sx);
vis[sy][sx] = 1;
while (!q.empty()) {
auto [y, x] = q.front();
q.pop();
if (dist[y][x] >= dist_bee[y][x] * s) continue;
for (int k = 0; k < 4; k++) {
int ny = y + yy[k], nx = x + xx[k];
if (ny < 1 || ny > n || nx < 1 || nx > n) continue;
if (vis[ny][nx]) continue;
if (grid[ny][nx] == 'T') continue;
if (ny == dy && nx == dx) return 1;
vis[ny][nx] = 1;
dist[ny][nx] = dist[y][x] + 1;
if (dist[ny][nx] >= dist_bee[ny][nx] * s) continue;
q.emplace(ny, nx);
}
}
return 0;
}
void compute_bee() {
queue<tuple<int,int,int>> q;
bool vis[nx][nx]; memset(vis, 0, sizeof vis);
for (auto [i, j] : hives) q.emplace(0, i, j), vis[i][j] = 1;
while (!q.empty()) {
auto [w, y, x] = q.front();
q.pop();
for (int k = 0; k < 4; k++) {
int ny = y + yy[k], nx = x + xx[k];
if (ny < 1 || ny > n || nx < 1 || nx > n) continue;
if (vis[ny][nx]) continue;
if (grid[ny][nx] == 'D' || grid[ny][nx] == 'T') continue;
vis[ny][nx] = 1;
dist_bee[ny][nx] = w + 1;
q.emplace(w + 1, ny, nx);
}
}
}
int main() {
ios_base::sync_with_stdio(0), cin.tie(0);
cin >> n >> s;
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= n; j++) {
cin >> grid[i][j];
if (grid[i][j] == 'M') sy = i, sx = j;
else if (grid[i][j] == 'D') dy = i, dx = j;
else if (grid[i][j] == 'H') hives.emplace_back(i, j);
}
}
for (int i = 1; i <= n; i++) for (int j = 1; j <= n; j++) dist_bee[i][j] = 1e9;
compute_bee();
int l = 0, r = n * n;
while (l < r) {
int mid = ceil(1.0 * (l + r) / 2.0);
if (check(mid)) l = mid;
else r = mid - 1;
}
if (check(l)) cout << l;
else cout << -1;
}
/*
7 3
TTTTTTT
TGGGGGT
TGGGGGT
MGGGGGD
TGGGGGT
TGGGGGT
THHHHHT
1
7 3
TTTTTTT
TGGGGGT
TGGGGGT
MGGTGGD
TGGGGGT
TGGGGGT
THHHHHT
7 3
TTTTTTT
TGGGGGT
TGGGGGT
MGGGGGD
TGGGGGT
TGGGGGT
TGHHGGT
2
*/
