#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 8e2 + 5;
int n, s;
char grid[N][N];
pair<int, int> init, home;
vector<pair<int, int>> hive;
vector<int> dx = {-1, 0, 1, 0}, dy = {0, 1, 0, -1};
int dmecho[N][N], dbee[N][N];
bool vmecho[N][N], vbee[N][N];
queue<pair<int, int>> qmecho, qbee;
bool bee_inbound(int x, int y) {
return x >= 1 && x <= n && y >= 1 && y <= n && !vbee[x][y] && grid[x][y] == 'G';
}
bool mecho_inbound(int x, int y) {
return x >= 1 && x <= n && y >= 1 && y <= n && !vmecho[x][y] && (grid[x][y] == 'G' || grid[x][y] == 'D');
}
bool valid(int m) {
// initialize
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= n; j++) {
dmecho[i][j] = dbee[i][j] = 1e18;
vmecho[i][j] = vbee[i][j] = false;
}
}
// mecho eats and bee move
for (auto&u : hive) {
int x = u.first, y = u.second;
dbee[x][y] = 0, qbee.push({x, y});
}
for (int i = 1; i <= n*n; i++) {
queue<pair<int, int>> nex;
while (qbee.size()) {
int x = qbee.front().first, y = qbee.front().second; qbee.pop();
for (int k = 0; k < 4; k++) {
int tox = x + dx[k], toy = y + dy[k];
if (!bee_inbound(tox, toy)) continue;
if (dbee[tox][toy] <= max(1ll, i - m + 1)) continue;
dbee[tox][toy] = max(1ll, i - m + 1), vbee[tox][toy] = true, nex.push({tox, toy});
}
}
swap(nex, qbee);
}
// debug
/*for (int i = 1; i <= n; i++) {
for (int j = 1; j <= n; j++) {
cout << (dbee[i][j] == 1e18 ? -1 : dbee[i][j]) << ' ';
}
cout << '\n';
}*/
// debug
int x = init.first, y = init.second;
dmecho[x][y] = 0, vmecho[x][y] = true, qmecho.push({x, y});
for (int i = 1; i <= (n*n + s - 1)/s; i++) {
for (int j = 1; j <= s; j++) {
queue<pair<int, int>> nex;
while (qmecho.size()) {
int x = qmecho.front().first, y = qmecho.front().second; qmecho.pop();
if (dmecho[x][y] >= dbee[x][y]) continue;
for (int k = 0; k < 4; k++) {
int tox = x + dx[k], toy = y + dy[k];
if (!mecho_inbound(tox, toy)) continue;
if (dmecho[tox][toy] <= i) continue;
dmecho[tox][toy] = i, vmecho[tox][toy] = true, nex.push({tox, toy});
}
}
swap(nex, qmecho);
}
}
x = home.first, y = home.second;
return dmecho[x][y] < dbee[x][y];
}
signed main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
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') init = {i, j};
else if (grid[i][j] == 'D') home = {i, j};
else if(grid[i][j] == 'H') hive.push_back({i, j});
}
}
int l = 0, r = 1000, ans = 0;
while (l <= r) {
int m = (l + r)/2;
if (valid(m)) ans = m, l = m + 1;
else r = m - 1;
}
cout << ans << '\n';
return 0;
}
