#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#define pb push_back
#define int long long
#define repp(i,x,n) for(int i=x;i<=n;i++)
#define rep(i,x,n) for(int i=x;i>=n;i--)
#define cy cout<<"YES"<<endl
#define cn cout<<"NO"<<endl
#define ca cout<<"Alice"<<endl
#define r0 return 0
#define fi first
#define se second
#define liow ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define jelek cout<<"jelek"<<endl
#define pii pair<int,int>
#define all(v) v.begin(),v.end()
#define pi pair<pair<int,int>,pair<int,int>>
#define p3 pair<int,pair<int,int>>
#define p2
#define tp tuple<int,int,int>
#define fl fflush(stdout)
#define ld long double
#define p5 pair<int,pair<pair<int,int>,pair<int,int>>>
#pragma GCC optimize ("O2")
#pragma GCC optimize ("unroll-loops")
using namespace std;
using namespace __gnu_pbds;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
typedef tree<pair<int,int>, null_type, less<pair<int,int>>, rb_tree_tag, tree_order_statistics_node_update> ordered_multiset;
typedef long long bryson;
const int mod=1e9+7;
const int SQMAX=635,INF=1e18;
//const int mod=998244353;
//const int MOD=1e6+3;
mt19937_64 rng((unsigned int) chrono::steady_clock::now().time_since_epoch().count());
pii dr[8]={{-1,0},{-1,1},{0,1},{1,1},{1,0},{1,-1},{0,-1},{-1,-1}};
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};
int dxx[4]={1,1,-1,-1};
int dyy[4]={1,-1,-1,1};
int mul(int x,int y){return (x%mod*y%mod)%mod;}
int expo(int b,int e){
if(e==0) return 1;
int tmp=expo(b,e/2);
if(e%2) return mul(tmp,mul(tmp,b));
else return mul(tmp,tmp);
}
const int maxn=1e5+5;
const int N=1e5;
const long double eps=1e-6;
signed main(){
ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
int n,s;cin>>n>>s;
char a[n+2][n+2];
repp(i,1,n) repp(j,1,n) cin>>a[i][j];
int bee[n+2][n+2];
queue<pii>q;
repp(i,1,n){
repp(j,1,n){
if(a[i][j]=='H'){
bee[i][j]=0;
q.push({i,j});
} else {
bee[i][j]=INF;
}
}
}
while(!q.empty()){
auto[x,y]=q.front();q.pop();
repp(i,0,3){
int nx=dx[i]+x,ny=dy[i]+y;
if(1<=nx && nx<=n && 1<=ny && ny<=n && (a[nx][ny]=='G' || a[nx][ny]=='M') && bee[nx][ny]>bee[x][y]+1){
bee[nx][ny]=bee[x][y]+1;
q.push({nx,ny});
}
}
}
int ans=-1;
int l=0,r=1000000000;
while(l<=r){
int mid=(l+r)/2;
// diem selama mid
int dist[n+2][n+2];
while(!q.empty()) q.pop();
repp(i,1,n){
repp(j,1,n){
dist[i][j]=INF;
if(a[i][j]=='M'){
dist[i][j]=0;
q.push({i,j});
}
}
}
auto[x,y]=q.front();
if(mid>=bee[x][y]){
r=mid-1;
continue;
}
bool tr=0;
while(!q.empty()){
auto[x,y]=q.front();q.pop();
if(a[x][y]=='D'){
tr=1;
break;
}
repp(i,0,3){
int nx=dx[i]+x,ny=dy[i]+y;
if(1<=nx && nx<=n && 1<=ny && ny<=n && a[nx][ny]!='T' && mid+(dist[x][y]+1)/s+1<=bee[nx][ny]){
if(dist[nx][ny]>dist[x][y]+1){
dist[nx][ny]=dist[x][y]+1;
q.push({nx,ny});
}
}
}
}
if(tr){
ans=mid;
l=mid+1;
} else {
r=mid-1;
}
}
cout<<ans<<endl;
}
