#include <bits/stdc++.h>
using namespace std;
using ii = pair<int,int>;
using ll = long long;
const int dx[] {0, -1, 0, 1};
const int dy[] {-1, 0, 1, 0};
constexpr int MAXS = 5+800;
constexpr int INF = 1e8;
char c[MAXS][MAXS];
int N,S, tb[MAXS][MAXS];
bool ok(int x, int y) {
return x >= 0 && y >= 0 && x < N && y < N;
}
void bfs_bees() {
queue<ii> q;
for (int i = 0; i < N; ++i) {
for (int j = 0; j < N; ++j) {
if (c[i][j] == 'H') {
q.push({i,j});
tb[i][j] = 0;
} else {
tb[i][j] = 10*INF;
}
}
}
while (!q.empty()) {
auto u = q.front(); q.pop();
for (int k = 0; k < 4; ++k) {
int newx = u.first+dx[k], newy = u.second+dy[k];
if (ok(newx, newy) && 1+tb[u.first][u.second] < tb[newx][newy] && (c[newx][newy] == 'G' || c[newx][newy] == 'M')) {
q.push({newx, newy});
tb[newx][newy] = 1+tb[u.first][u.second];
}
}
}
}
ii dist[MAXS][MAXS];
bool can(const ii& source, const ii& target, int t) {
if (t >= tb[source.first][source.second]) return false;
for (int i = 0; i < N; ++i) {
for (int j = 0; j < N; ++j) {
dist[i][j] = {10*INF, 0};
}
}
queue<array<int,2>> q; q.push({source.first, source.second});
dist[source.first][source.second] = {t, S};
while (!q.empty()) {
auto u = q.front(); q.pop();
if (u[0] == target.first && u[1] == target.second) return true;
for (int k = 0; k < 4; ++k) {
int newx = u[0]+dx[k], newy = u[1]+dy[k];
ii newcost = dist[u[0]][u[1]];
newcost.second--;
if (newcost.second <= 0) {
newcost.first++;
newcost.second = S;
}
if (ok(newx, newy) && (c[newx][newy] == 'G' || c[newx][newy] == 'D' || c[newx][newy] == 'M') && newcost.first < tb[newx][newy] && newcost.first < dist[newx][newy].first) {
q.push({newx, newy});
dist[newx][newy] = newcost;
}
}
}
return false;
}
int main() {
ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
cin >> N >> S;
ii start, target;
for (int i = 0; i < N; ++i) {
for (int j = 0; j < N; ++j) {
cin >> c[i][j];
if (c[i][j] == 'M') {
start = {i,j};
} else if (c[i][j] == 'D') {
target = {i,j};
}
}
}
bfs_bees();
int low = 0, high = INF, best = -1;
while (low <= high) {
int mid = (low+high) >> 1;
if (can(start, target, mid)) {
low = 1+mid;
best = mid;
} else {
high = mid-1;
}
}
cout << best << '\n';
return 0;
}
