//#pragma GCC optimize("O3,unroll-loops,Ofast")
//#pragma GCC target("avx2,bmi,bmi2,popcnt,lzcnt")
#include <bits/stdc++.h>
//#include <cstdio>
//#include <iostream>
using namespace std;
#define MAX 100000007
#define pb push_back
//#define mp make_pair
#define int long long
#define f first
#define s second
#define vi vector<int>
#define pii pair<int,int>
#define si set<int>
#define vpii vector<pair<int,int>>
const int mod = 1e9+7;
const int INF = 1e18;
// myMap.begin()->first : key
// myMap.begin()->second : value
int epow(int a,int b){int ans=1;while(b){if(b&1) ans*=a;a*=a;ans%=mod;a%=mod;b>>=1;}return ans%mod;}
int gcd(int a,int b) {if(a<b)swap(a,b);while(b){int tmp=b;b=a%b;a=tmp;}return a;}
int mul(int a,int b)
{
return ((a%mod)*(b%mod))%mod;
}
int calc(int x)
{
int ans=0;
while(x)
{
ans += x%10;
x/=10;
}
return ans;
}
int dx[] = {-1, 0, 1, 0};
int dy[] = {0, -1, 0, 1};
int n,s;
vector<vector<char>> grid(1000,vector<char>(1000));
bool valid_sq(int x, int y) {
return x >= 0 && x < n && y >= 0 && y < n &&
(grid[x][y] == 'G' || grid[x][y] == 'M');
}
bool mecho_reached(int mecho_dis, int bees_dis) {
return mecho_dis / s < bees_dis;
}
void solve() {
cin >> n >> s;
pii bear,home;
vector<pii> hives;
for(int i=0;i<n;i++)
{
for(int j=0;j<n;j++)
{
cin >> grid[i][j];
if(grid[i][j]=='H') hives.pb({i,j});
if(grid[i][j]=='M') bear = {i,j};
if(grid[i][j]=='D') home = {i,j};
}
}
vector<vector<int>> d(n+2,vector<int>(n+2,INF));
queue<pii> q;
for(int i=0;i<hives.size();i++)
{
q.push({hives[i]});
d[hives[i].f][hives[i].s]=0;
}
while(q.size())
{
int x = q.front().first, y = q.front().second;
q.pop();
for (int i=0;i<4;i++)
{
int nx = x + dx[i], ny = y + dy[i];
if (valid_sq(nx, ny) && d[nx][ny]==INF)
{
d[nx][ny] = d[x][y] + 1;
q.push({nx, ny});
}
}
}
int l=0,r=n*n;
while(l<=r)
{
int time = (l+r)/2;
queue<pii> q;
vector<vi> dbear(n+2,vi(n+2,INF));
q.push(bear);
dbear[bear.f][bear.s]=0;
while(q.size())
{
int x = q.front().first, y = q.front().second;
q.pop();
for (int i=0;i<4;i++)
{
int nx=x+dx[i],ny=y+dy[i];
if (valid_sq(nx, ny) && dbear[nx][ny]==INF &&
mecho_reached(dbear[x][y] + 1,
d[nx][ny] - time)) {
q.push({nx, ny});
dbear[nx][ny] = dbear[x][y] + 1;
}
}
}
bool flag = false;
for (int i = 0; i < 4; i++) {
int nx = home.f + dx[i], ny = home.s + dy[i];
if (valid_sq(nx, ny) &&
mecho_reached(dbear[nx][ny],
d[nx][ny] - time) && dbear[nx][ny]!=INF )
{
flag = true;
}
}
if (flag) {
l = time + 1;
} else {
r = time - 1;
}
}
cout << l-1 << endl;
return;
}
int32_t main() {
// freopen("lasers.in", "r", stdin);
// freopen("lasers.out", "w", stdout);
std::ios_base::sync_with_stdio(false);
std::cin.tie(nullptr);
int t=1;
// cin >> t;
while (t--) solve();
return 0;
}
