#include <bits/stdc++.h>
#define INF 1000000000
#define NMAX 800
#define x first
#define y second
using namespace std;
int n, s;
pair<int, int> start, home;
char m[NMAX+1][NMAX+1];
int dist_bees[NMAX+1][NMAX+1], dist_m[NMAX+1][NMAX+1];
int dif_min[NMAX+1][NMAX+1];
int dx[4]={0, -1, 0, 1};
int dy[4]={-1, 0, 1, 0};
bool valid(int x, int y)
{
return (x>=1 && x<=n && y>=1 && y<=n);
}
bool possible(int minutes)
{
for(int i=1; i<=n; i++)
{
for(int j=1; j<=n; j++)
dist_m[i][j]=INF;
}
dist_m[start.x][start.y]=minutes;
queue<pair<int, int>> q;
q.push(start);
while(!q.empty())
{
auto [x, y]=q.front();
q.pop();
for(int d=0; d<4; d++)
{
int new_x=x+dx[d], new_y=y+dy[d];
if(valid(new_x, new_y) && (m[new_x][new_y]=='G' || m[new_x][new_y]=='M' || m[new_x][new_y]=='D') && dist_m[new_x][new_y]==INF && dist_bees[new_x][new_y]>dist_m[x][y]+1)
{
dist_m[new_x][new_y]=dist_m[x][y]+1;
q.push({new_x, new_y});
}
}
}
return (dist_m[home.x][home.y]!=INF);
}
int solve()
{
int st=0, dr=INF, ans=-1;
while(st<=dr)
{
int mij=st+(dr-st)/2;
if(possible(mij))
{
ans=mij;
st=mij+1;
}
else dr=mij-1;
}
if(ans!=-1) ans/=s;
return ans;
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> s;
queue<pair<int, int>> q;
for(int i=1; i<=n; i++)
{
for(int j=1; j<=n; j++)
{
dist_bees[i][j]=dist_m[i][j]=INF;
dif_min[i][j]=INF;
cin >> m[i][j];
if(m[i][j]=='H') {dist_bees[i][j]=0; q.push({i, j});}
if(m[i][j]=='M') start={i, j};
if(m[i][j]=='D') home={i, j};
}
}
while(!q.empty())
{
auto [x, y]=q.front();
q.pop();
for(int d=0; d<4; d++)
{
int new_x=x+dx[d], new_y=y+dy[d];
if(valid(new_x, new_y) && (m[new_x][new_y]=='G' || m[new_x][new_y]=='M') && dist_bees[new_x][new_y]==INF)
{
dist_bees[new_x][new_y]=dist_bees[x][y]+s;
q.push({new_x, new_y});
}
}
}
cout << solve();
return 0;
}
