/* * * * * * * * * *\
* 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';
}
bool nvalid(int x,int y)
{
return x>=0&&y>=0&&x<n&&y<n;
}
bool check(int Time)
{
v(v(int))newdist;
newdist=dist;
FOR(i,maxn)
FOR(j,maxn)
{
vis[i][j]=0;
if(a[i][j]=='T'||a[i][j]=='H'||a[i][j]=='M')
vis[i][j]=1;
}
queue<p(pii,int)>nq;
nq.push({Mecho,foot});
newdist[Mecho.ff][Mecho.ss]=Time;
while(nq.size())
{
pii f=nq.front().ff;
int lft=nq.front().ss;
nq.pop();
FOR(i,4)
{
int x=f.ff+dx[i],y=f.ss+dy[i];
if(nvalid(x,y)&&(a[x][y]=='G'||a[x][y]=='D'))
{
if(!vis[x][y])
{
if(lft)
{
if(newdist[x][y]>newdist[f.ff][f.ss])
{
newdist[x][y]=newdist[f.ff][f.ss];
nq.push({{x,y},lft-1});
vis[x][y]=1;
}
}
else
{
if(newdist[x][y]>newdist[f.ff][f.ss]+1)
{
newdist[x][y]=newdist[f.ff][f.ss];
nq.push({{x,y},foot});
vis[x][y]=1;
}
}
}
}
}
}
return newdist[House.ff][House.ss]!=inf;
}
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;
q.push({x,y});
dist[x][y]=dist[f.ff][f.ss]+1;
}
else if(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 l=1,r=800*800,ans=0;
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-1;
}
