#pragma GCC optimize("O3", "inline")
#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef long double ld;
#define pb push_back
#define ub upper_bound
const ll INF = 1e18 + 100;
vector<int> ra = {-1, 0, 1, 0};
vector<int> ca = {0, 1, 0, -1};
int f(int n, vector<string> &a, int s, int m, vector<int> &sp, vector<int> &ep, vector<vector<ll>> &ftm)
{
vector<vector<int>> v(n, vector<int>(n, 0));
if (ftm[sp[0]][sp[1]] <= m)
return 0;
queue<vector<int>> q;
q.push({sp[0], sp[1], m});
v[sp[0]][sp[1]] = 1;
while (!q.empty())
{
for (int i = 0; i < s; i++)
{
int sz = q.size();
for (int j = 0; j < sz; j++)
{
auto del = q.front();
q.pop();
for (int d = 0; d < 4; d++)
{
int nr = del[0] + ra[d], nc = del[1] + ca[d];
if (nr >= 0 && nr < n && nc >= 0 && nc < n && (a[nr][nc] == 'G' || a[nr][nc] == 'D') && ftm[nr][nc] > del[2] && !v[nr][nc])
{
if(nr == ep[0] && nc == ep[1]) return 1;
q.push({nr, nc, (i == s - 1 ? del[2] + 1 : del[2])});
v[nr][nc] = 1;
}
}
}
}
}
return 0;
}
ll solve()
{
int n, s;
cin >> n >> s;
vector<string> a(n);
for (int i = 0; i < n; i++)
cin >> a[i];
vector<int> sp(2), ep(2);
for (int i = 0; i < n; i++)
for (int j = 0; j < n; j++)
{
if (a[i][j] == 'M')
sp = {i, j};
if (a[i][j] == 'D')
ep = {i, j};
}
vector<vector<ll>> ftm(n, vector<ll>(n, INF));
{
queue<pair<int, int>> q;
for (int i = 0; i < n; i++)
for (int j = 0; j < n; j++)
{
if (a[i][j] == 'H')
{
ftm[i][j] = 0;
q.push({i, j});
}
}
while (!q.empty())
{
int sz = q.size();
for (int i = 0; i < sz; i++)
{
auto del = q.front();
q.pop();
for (int d = 0; d < 4; d++)
{
int nr = del.first + ra[d], nc = del.second + ca[d];
if (nr >= 0 && nr < n && nc >= 0 && nc < n && (a[nr][nc] == 'G' || a[nr][nc] == 'M') && ftm[nr][nc] == INF)
{
ftm[nr][nc] = ftm[del.first][del.second] + 1;
q.push({nr, nc});
}
}
}
}
}
int l = 0, h = 2 * n, ma = -1;
while (l <= h)
{
int m = (l + h) / 2;
if (f(n, a, s, m, sp, ep, ftm))
{
ma = m;
l = m + 1;
}
else
h = m - 1;
}
return ma;
}
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int t = 1;
while (t--)
{
ll x = solve();
cout << x << "\n";
}
return 0;
}
