/* * * * * * * * * *\
* 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<<60LL;
const int mod=1e9+7;
const int maxn=808;
int n,foot;
pii Mecho,House;
char a[maxn][maxn];
bool vis[maxn][maxn];
queue<pii>q;
v(v(int)) dist;
int dx[] {-1,1,0,0};
int dy[] {0,0,-1,1};
bool valid(int x,int y)
{
return x>=0&&y>=0&&x<n&&y<n&&(a[x][y]=='G'||a[x][y]=='D');
}
int jump[maxn][maxn];
bool finish=0;
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(valid(x,y))
{
if(!vis[x][y])
{
vis[x][y]=1;
if(jump[f.ff][f.ss]){
q.push({x,y});
dist[x][y]=dist[f.ff][f.ss];
jump[x][y]=jump[f.ff][f.ss]-1;
} else {
q.push({x,y});
dist[x][y]=dist[f.ff][f.ss]+1;
if(finish)
jump[x][y]=foot;
}
}
else if(!finish&&dist[x][y]>dist[f.ff][f.ss]+1)
{
dist[x][y]=dist[f.ff][f.ss]+1;
q.push({x,y});
}
}
}
}
}
signed main()
{
SIO("");
cin>>n>>foot;
dist.resize(maxn);
FOR(i,maxn)
dist[i].resize(maxn);
FOR(i,n)
FOR(j,n)
{
cin>>a[i][j];
dist[i][j]=inf;
if(a[i][j]=='M')
Mecho= {i,j};
else if(a[i][j]=='H')
q.push({i,j}),vis[i][j]=1,dist[i][j]=0;
else if(a[i][j]=='T')
vis[i][j]=1;
else if(a[i][j]=='D')
House= {i,j};
}
solve();
int len=dist[House.ff][House.ss];
int l=1,r=inf,ans=-1;
finish=1;
while(l<=r)
{
int mid=l+(r-l)/2;
FOR(i,maxn)
FOR(j,maxn)
dist[i][j]=inf,vis[i][j]=0,jump[i][j]=0;
dist[Mecho.ff][Mecho.ss]=mid;
jump[Mecho.ff][Mecho.ss]=foot;
q.push(Mecho);
solve();
if(dist[House.ff][House.ss]<len)
ans=max(ans,mid),l=mid+1;
else
r=mid-1;
}
cout<<ans;
}
