#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define ff first
#define ss second
#define pb push_back
#define mk make_pair
#define IOS ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int n,m;
int b[805][806];
queue<pair<int,int> > q;
int stx, sty;
int cnt[805][805];
int tmp[805][805];
bool check = 0;
char ch[805][805];
int main() {
IOS
cin >> n >> m;
for(int i = 1; i <= n; i ++) {
for(int j = 1; j <= n; j ++) {
cin >> ch[i][j];
if(ch[i][j] == 'H') {
b[i][j] = 1;
q.push({i,j});
}
if(ch[i][j] == 'M') {
stx = i;
sty = j;
}
}
}
while(q.size() > 0) {
int x = q.front().ff;
int y = q.front().ss;
q.pop();
if(x > 1 && b[x - 1][y] == 0 && ch[x - 1][y] != 'T' && ch[x - 1][y] != 'D') {
q.push({x - 1, y});
b[x - 1][y] = b[x][y] + 1;
}
if(x < n && b[x + 1][y] == 0 && ch[x + 1][y] != 'T' && ch[x + 1][y] != 'D') {
q.push({x + 1, y});
b[x + 1][y] = b[x][y] + 1;
}
if(y > 1 && b[x][y - 1] == 0 && ch[x][y - 1] != 'T' && ch[x][y - 1] != 'D') {
q.push({x, y - 1});
b[x][y - 1] = b[x][y] + 1;
}
if(y < n && b[x][y + 1] == 0 && ch[x][y + 1] != 'T' && ch[x][y + 1] != 'D') {
q.push({x, y + 1});
b[x][y + 1] = b[x][y] + 1;
}
}
for(int i = 1; i <= n; i ++) {
for(int j = 1; j <= n; j ++) {
if(b[i][j] == 0) b[i][j] = 1e9;
else b[i][j] --;
}
}
int l = 0;
int r = n * n;
while(l < r) {
int mid = (l + r + 1) / 2;
memset(cnt, -1, sizeof(cnt));
while(q.size() > 0) q.pop();
//
q.push({stx, sty});
if(mid >= b[stx][sty]) {
r = mid - 1;
continue;
}
cnt[stx][sty] = mid;
bool ok = 0;
//
while(q.size() > 0) {
int x = q.front().ff;
int y = q.front().ss;
q.pop();
if(ch[x][y] == 'D') {
ok = 1;
break;
}
for(int i = 1; i <= m; i ++) {
for(int j = 0; j <= i; j ++) {
int xx = x - j;
int yy = y - (i - j);
if(cnt[xx][yy] == -1 && cnt[x][y] + 1 < b[xx][yy] && ch[xx][yy] != 'T') {
q.push({xx,yy});
cnt[xx][yy] = cnt[x][y] + 1;
}
}
for(int j = 0; j <= i; j ++) {
int xx = x - (i - j);
int yy = y + j;
if(cnt[xx][yy] == -1 && cnt[x][y] + 1 < b[xx][yy] && ch[xx][yy] != 'T') {
q.push({xx,yy});
cnt[xx][yy] = cnt[x][y] + 1;
}
}
for(int j = 0; j <= i; j ++) {
int xx = x + j;
int yy = y + (i - j);
if(cnt[xx][yy] == -1 && cnt[x][y] + 1 < b[xx][yy] && ch[xx][yy] != 'T') {
q.push({xx,yy});
cnt[xx][yy] = cnt[x][y] + 1;
}
}
for(int j = 0; j <= i; j ++) {
int xx = x + (i - j);
int yy = x - j;
if(cnt[xx][yy] == -1 && cnt[x][y] + 1 < b[xx][yy] && ch[xx][yy] != 'T') {
q.push({xx,yy});
cnt[xx][yy] = cnt[x][y] + 1;
}
}
}
}
if(ok == 1) {
check = 1;
l = mid;
}
else r = mid - 1;
}
if(check == 1){
cout << l;
}
else cout << -1;
}
