#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> pii;
const int MX=1000,inf=0x7fffffff;
int dx[4]={1,-1,0,0},dy[4]={0,0,1,-1};
char G[MX][MX];
int d[MX][MX],d1[MX][MX];
int n,s,sx,sy,fx,fy,ans=-1;
queue<int> Q1[2];
int bfs(int time){
memset(d1,0,sizeof(d1));
d1[sx][sy]=-1;
queue<int> Q;
Q.push(sx*MX+sy);
while(!Q.empty()){
int x=Q.front()/MX,y=Q.front()%MX;Q.pop();
// printf("x=%d,y=%d time=%d\n",x,y,d1[x][y]/s+time);
if (time>0&&d1[x][y]/s+time>=d[x][y])continue;
for (int i=0;i<4;i++){
int X=x+dx[i],Y=y+dy[i];
if (X<1||X>n||Y<1||Y>n)continue;
if (X==fx&&Y==fy)return 1;
if (G[X][Y]=='T'||G[X][Y]=='H'||d1[X][Y]>0)continue;
d1[X][Y]=d1[x][y]+1;
Q.push(X*MX+Y);
// printf("INQ T:%d X:%d Y:%d\n",d1[X][Y],X,Y);
}
// printf("#\n");
// for (int i=1;i<=n;i++){
// for (int j=1;j<=n;j++)printf("%2d",d1[i][j]);printf("\n");
// }
}
return 0;
}
int main(){
scanf("%d%d",&n,&s);
memset(d,-1,sizeof(d));
for (int i=1;i<=n;i++){
scanf("%s",G[i]+1);
for (int j=1;j<=n;j++){
if (G[i][j]=='H')d[i][j]=0,Q1[0].push(i*MX+j);
if (G[i][j]=='M')sx=i,sy=j;
if (G[i][j]=='D')d[i][j]=inf,fx=i,fy=j;
}
}
int cnt=0;
for (int t=1;;t++){
if (Q1[cnt].empty())break;
while(!Q1[cnt].empty()){
int xy=Q1[cnt].front();Q1[cnt].pop();
int x=xy/MX,y=xy%MX;
for (int i=0;i<4;i++){
int X=x+dx[i],Y=y+dy[i];
if (d[X][Y]>=0||G[X][Y]=='D'||G[X][Y]=='T')continue;
d[X][Y]=t;
Q1[1-cnt].push(X*MX+Y);
}
}
cnt=1-cnt;
}
for (int t=d[sx][sy];t>=0;t--)
if (bfs(t)){
printf("%d\n",t);
return 0;
}
printf("-1");
/* if (bfs(-1)){
ans=0;
int l=0,m,r=d[sx][sy];
while(l<r){
m=(l+r)/2;
if (bfs(m)){
l=m+1;
ans=m;
}else{
r=m-1;
}
}
}
printf("%d\n",ans);*/
return 0;
}
