#include <bits/stdc++.h>
#define N 810
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
ll read()
{
char c=getchar();bool flag=0;ll x=0;
while(c<'0'||c>'9'){if(c=='-')flag=1;c=getchar();}
while(c>='0'&&c<='9'){x=(x<<3)+(x<<1)+c-'0';c=getchar();}
return flag?-x:x;
}
queue<ll> q;
char a[N][N];
ll b[N][N],vis[N][N];
int ax[4]={1,0,-1,0},n,s,sx,sy,ex,ey;
int ay[4]={0,1,0,-1};
void bfs()
{
while(q.size()!=0)
{
ll x=q.front()/N,y=q.front()%N;
q.pop();
for(ll i=0;i<4;i++)
{
//cout<<"++";
ll dx=x+ax[i];
ll dy=y+ay[i];
if(a[dx][dy]=='G'&&b[dx][dy]==-1)
{
//cout<<"++";
b[dx][dy]=b[x][y]+s;
q.push(dx*N+dy);
}
}
}
}
bool check(ll mid)
{
for(ll i=1;i<=n;i++)
{
for(ll j=1;j<=n;j++) vis[i][j]=-1;
}
//cout<<"++";
if(b[sx][sy]<=mid*s) return false;
//cout<<"++";
vis[sx][sy]=mid*s;
q.push(sx*N+sy);
while(q.size()!=0)
{
ll x=q.front()/N,y=q.front()%N;
q.pop();
//cout<<"++";
for(ll i=0;i<4;i++)
{
ll dx=x+ax[i];
ll dy=y+ay[i];
if((a[dx][dy]=='G'&&vis[dx][dy]==-1 && b[dx][dy]>vis[x][y]+1)||(a[dx][dy]=='G'&&vis[dx][dy]==-1))
{
//cout<<"++";
if(dx==ex&&dy==ey) return true;
vis[dx][dy]=vis[x][y]+1;
q.push(dx*N+dy);
}
}
}
return false;
}
int main()
{
n=read(),s=read();
for(ll i=1;i<=n;i++)
{
for(ll j=1;j<=n;j++) b[i][j]=-1;
}
for(ll i=1;i<=n;i++)
{
for(ll j=1;j<=n;j++)
{
cin>>a[i][j];
if(a[i][j]=='M') sx=i,sy=j,a[i][j]='G';
if(a[i][j]=='D') ex=i,ey=j;
if(a[i][j]=='H') q.push(i*N+j),b[i][j]=0;
}
}
bfs();
ll r=n*n,l=0,ans=-1;
while(l<=r)
{
ll mid=(l+r)/2;
if(check(mid)) ans=mid,l=mid+1;
else r=mid-1;
}
printf("%lld\n",ans);
}
