#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ull unsigned long long
#define pb(e) push_back(e)
#define sv(a) sort(a.begin(),a.end())
#define sa(a,n) sort(a,a+n)
#define mp(a,b) make_pair(a,b)
#define vf first
#define vs second
#define ar array
#define all(x) x.begin(),x.end()
const int inf = 0x3f3f3f3f;
const int mod = 1000000007;
const double PI=3.14159265358979323846264338327950288419716939937510582097494459230;
bool remender(ll a , ll b){return a%b;}
void clear( std::queue<pair<int,int>> &q )
{
std::queue<pair<int,int>> empty;
std::swap( q, empty );
}
void solve(){
int dx[4] = {0,0,-1,1} , dy[4] = {1,-1,0,0};
int n , s;
cin >> n >> s;
char arr[n][n];
for(int i = 0; i < n; i++){
for(int j = 0; j < n; j++)cin >> arr[i][j];
}
queue<pair<int,int>> q;
ll dis[n][n];
for(int i = 0; i < n; i++){
for(int j = 0; j < n; j++)dis[i][j] = 1e18;
}
bool vis[n][n];
memset(vis,0,sizeof vis);
pair<int,int> end, start;
for(int i = 0; i < n; i++){
for(int j = 0; j < n; j++){
if(arr[i][j] == 'H'){q.push(mp(i,j));dis[i][j] = 0;vis[i][j] = 1;}
if(arr[i][j] == 'D')end = mp(i,j);
if(arr[i][j] == 'M')start = mp(i,j);
}
}
while(q.size()){
pair<int,int> node = q.front();
q.pop();
for(int i = 0; i < 4; i++){
if(node.vf + dx[i] >= 0 && node.vf + dx[i] < n && node.vs + dy[i] < n && node.vs + dy[i] >= 0 && !vis[node.vf + dx[i]][node.vs + dy[i]] && arr[node.vf + dx[i]][node.vs + dy[i]] == 'G'){
q.push(mp(node.vf + dx[i] , node.vs + dy[i]));
dis[node.vf + dx[i]][node.vs + dy[i]] = dis[node.vf][node.vs] + 1;
vis[node.vf + dx[i]][node.vs + dy[i]] = 1;
}
}
}
int dis1[n][n];
int l = 0 , r = n * n + 3;
if(dis[start.vf][start.vs] != 1e18)r = dis[start.vf][start.vs]-1;
int ans = -1;
while(l <= r){
int mid = (l + r)/2;
dis1[start.vf][start.vs] = s * mid;
memset(vis,0,sizeof vis);
vis[start.vf][start.vs] = 1;
clear(q);
q.push(mp(start.vf , start.vs));
while(q.size() && !vis[end.vf][end.vs]){
pair<int,int> node = q.front();
q.pop();
for(int i = 0; i < 4; i++){
if(node.vf + dx[i] >= 0 && node.vf + dx[i] < n && node.vs + dy[i] < n && node.vs + dy[i] >= 0 && !vis[node.vf + dx[i]][node.vs + dy[i]] && (arr[node.vf + dx[i]][node.vs + dy[i]] == 'G' || arr[node.vf + dx[i]][node.vs + dy[i]] == 'D') && dis[node.vf + dx[i]][node.vs + dy[i]] > (dis1[node.vf][node.vs] + 1)/s){
q.push(mp(node.vf + dx[i] , node.vs + dy[i]));
dis1[node.vf + dx[i]][node.vs + dy[i]] = dis1[node.vf][node.vs] + 1;
vis[node.vf + dx[i]][node.vs + dy[i]] = 1;
}
}
}
if(vis[end.vf][end.vs]){
ans = mid;
l = mid + 1;
}
else r = mid - 1;
}
cout << ans << '\n';
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
//int t;cin >> t;while(t--)
solve();
return 0;
}
