#include <bits/stdc++.h>
using namespace std;
int n,s;
vector<vector<char>> grid;
vector<pair<int,int>> hives;
pair<int,int> root,obj;
vector<vector<int>> mapa;
vector<vector<bool>> visit;
vector<vector<int>> dp;
int sx[4] = {0,0,1,-1};
int sy[4] = {1,-1,0,0};
bool ok(int x, int y){
return x < n && y < n && x >= 0 && y >= 0;
}
void bfs(){
queue<pair<int,int>> cola;
for(auto h : hives){
cola.push(h);
}
while(cola.size()){
auto q = cola.front();
cola.pop();
int x = q.first;
int y = q.second;
for(int i=0; i<4; i++){
int nx = x + sx[i];
int ny = y + sy[i];
if(ok(nx,ny)){
if(mapa[nx][ny] != -1)continue;
if(grid[nx][ny] == 'G' || grid[nx][ny] == 'M'){
mapa[nx][ny] = mapa[x][y]+1;
cola.push({nx,ny});
}
}
}
}
}
/*
bool dfs(int x, int y,int k){
if(x == obj.first && y == obj.second)return true;
visit[x][y] = true;
bool b = false;
for(int i=0; i<4; i++){
int nx = x+sx[i];
int ny = y+sy[i];
if(ok(nx,ny)){
if(grid[nx][ny] == 'G' || grid[nx][ny] == 'D'){
if(visit[nx][ny]) continue;
if(mapa[nx][ny] > k){
b = max(b,dfs(nx,ny,k));
}
}
}
}
return b;
}
*/
int dfs(int x, int y,int cost, int steps){
//cout << x << " " << y << " " << cost << " " << steps << endl;
//cout << dp[x][y] << endl;
if(x == obj.first && y == obj.second) return 1e9;
if(mapa[x][y] - cost < 0) return -1;
if(dp[x][y] >= mapa[x][y] - cost) return -1;
dp[x][y] = mapa[x][y] - cost;
if(steps == s){
steps = 1;
cost++;
}
int sol = -1;
for(int i=0; i<n; i++){
int nx = x+sx[i];
int ny = y+sy[i];
if(ok(nx,ny)){
if(grid[nx][ny] == 'G' || grid[nx][ny] == 'D'){
int k = dfs(nx,ny,cost,steps+1);
sol = max(sol,k);
//cout << nx << " " << ny << " k: " << k << " sol: " << sol << endl;
}
}
}
//cout << x << " " << y << " " << cost << " sol: " << sol << endl;
if(sol != -1) return min(sol,dp[x][y]);
return -1;
}
int main(){
ios::sync_with_stdio(false);
cin.tie(0);
cin >> n >> s;
grid.assign(n,vector<char> (n));
mapa.assign(n,vector<int>(n,-1));
for(int i=0; i<n; i++){
for(int j=0; j<n; j++){
cin >> grid[i][j];
if(grid[i][j] == 'H'){
hives.push_back({i,j});
mapa[i][j] = 0;
}
if(grid[i][j] == 'M'){
root = {i,j};
}
if(grid[i][j] == 'D'){
obj = {i,j};
}
}
}
bfs();
/*
for(int i=0; i<n; i++){
for(int j=0; j<n; j++){
cout << mapa[i][j] << " ";
}
cout << endl;
}
*/
dp.assign(n,vector<int>(n,-1));
cout << dfs(root.first,root.second,1,0) << endl;
return 0;
/*
int lo = 1, hi = n*n, res = -1;
while(lo <= hi){
int mid = (lo+hi)/2;
int k = dfs(root.first,root.second,s*mid);
if(k - mid > res){
res = mid;
lo = mid+1;
}else hi = mid-1;
}
cout << res << endl;
*/
}
