/* * * * * * * * * *\
* Author: Haidara *
* LANG: C++17 *
* PROB: *
\* * * * * * * * * */
#include<bits/stdc++.h>
#define fast ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define int long long
#define rep(i,x,n) for(int i=x;i<(n);i++)
#define FOR(i,n) rep(i,0,n)
#define per(i,x,n) for(int i=x;i>(n);i--)
#define ROF(i,x) for(int i=x;i>=0;i--)
#define v(i) vector< i >
#define p(i,j) pair< i , j >
#define pii pair<int,int>
#define m(i,j) map< i , j >
#define um(i,j) unordered_map< i , j >
#define pq(i) priority_queue< i >
#define ff first
#define all(x) x.begin(),x.end()
#define ss second
#define pp push_back
using namespace std;
void SIO(string name="")
{
if(name!="")
{
freopen((name+".in").c_str(),"r",stdin);
freopen((name+".out").c_str(),"w",stdout);
}
}
const int inf=1LL<<62LL;
const int mod=1e9+7;
const int maxn=808;
char a[maxn][maxn];
int n,jump;
pii M,D;
queue<pii>q;
int dist[maxn][maxn],dx[] {-1,1,0,0},dy[] {0,0,1,-1};
bool valid(int x,int y)
{
return x>=0&&y>=0&&x<n&&y<n&&a[x][y]!='T'&&a[x][y]!='H';
}
void solve()
{
while(q.size())
{
pii f=q.front();
q.pop();
FOR(i,4)
{
int x=f.ff+dx[i],y=f.ss+dy[i];
if(x>=0&&y>=0&&x<n&&y<n&&a[x][y]=='G'&&dist[x][y]==inf)
dist[x][y]=dist[f.ff][f.ss]+jump,q.push({x,y});
}
}
}
bool check(int st)
{
queue<p(pii,int)>qq;
if(st*jump>=dist[M.ff][M.ss])
return 0;
qq.push({M,st*jump});
bool vis[maxn][maxn];
FOR(i,maxn)
FOR(j,maxn)
vis[i][j]=0;
bool ret=0;
vis[M.ff][M.ss]=1;
while(qq.size())
{
pii f=qq.front().ff;
int curr=qq.front().ss;
qq.pop();
if(f==D)
ret=1;
FOR(i,4)
{
int x=f.ff+dx[i],y=f.ss+dy[i];
if(valid(x,y))
{
if(dist[x][y]>curr+1&&!vis[x][y])
qq.push({{x,y},curr+1}),vis[x][y]=1;
}
}
}
return ret;
}
signed main()
{
SIO("");
cin>>n>>jump;
FOR(i,n)
FOR(j,n)
{
dist[i][j]=inf;
cin>>a[i][j];
if(a[i][j]=='M')
M= {i,j},a[i][j]='G';
else if(a[i][j]=='D')
D= {i,j};
else if(a[i][j]=='H')
q.push({i,j}),dist[i][j]=0;
}
solve();
int l=1,r=maxn*maxn*2,ans=-1;
while(l<=r)
{
int mid=l+(r-l)/2;
if(check(mid))
ans=max(ans,mid),l=mid+1;
else
r=mid-1;
}
cout<<ans;
}
