#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define gcd __gcd
#define sz(v) (int) v.size()
#define pb push_back
#define pi pair<int,int>
#define all(v) (v).begin(), (v).end()
#define compact(v) (v).erase(unique(all(v)), (v).end())
#define FOR(i, a, b) for(int i = (a); i <= (b); i++)
#define int long long
using ll = long long;
using ld = long double;
using ull = unsigned long long;
template<typename T> bool ckmx(T& a, const T& b){if(a < b) return a = b, true; return false;}
template<typename T> bool ckmn(T& a, const T& b){if(a > b) return a = b, true; return false;}
const int N = 1e3+5;
const ll MOD = 1e9+7;
const ll INF = 1e18;
const int dx[4] = {1, -1, 0, 0};
const int dy[4] = {0, 0, 1, -1};
int n, s, d[N][N], vis[N][N];
char a[N][N];
bool init(int x, int y){
return (x >= 1 && x <= n) && (y >= 1 && y <= n) && a[x][y] != 'T';
}
bool good(int time){
pi st, ed;
FOR(i, 1, n){
FOR(j, 1, n){
if(a[i][j] == 'M'){
st = make_pair(i,j);
vis[i][j] = 0;
}
else{
if(a[i][j] == 'D'){
ed = make_pair(i, j);
}
vis[i][j] = 1e9;
}
}
}
/* broke test without checking
7 3
GTGGGGG
GTGGGGG
GTGGGGG
HMGGGGD
GTGGGGG
GTGGGGG
GTGGGGG
*/
if(time >= d[st.fi][st.se]) return false;
queue<pair<int,int>> q;
q.push(st);
while(sz(q)){
pi e = q.front(); q.pop();
int x = e.fi, y = e.se;
for(int i = 0; i < 4; i++){
int xx = x + dx[i];
int yy = y + dy[i];
if(init(xx, yy) && vis[xx][yy] == 1e9 && a[xx][yy] != 'H'){
int n_dist = (vis[x][y] + 1) / s;
if(n_dist < d[xx][yy] - time){
vis[xx][yy] = vis[x][y] + 1;
q.push(make_pair(xx, yy));
}
}
}
}
return vis[ed.fi][ed.se] != 1e9;
}
void solve()
{
cin >> n >> s;
FOR(i, 1, n){
FOR(j, 1, n){
cin >> a[i][j];
}
}
queue<pair<int,int>> q;
FOR(i, 1, n){
FOR(j, 1, n){
if(a[i][j] == 'H'){
q.push(make_pair(i,j));
}
else d[i][j] = 1e9;
}
}
while(sz(q)){
pi e = q.front(); q.pop();
int x = e.fi, y = e.se;
for(int i = 0; i < 4; i++){
int xx = x + dx[i];
int yy = y + dy[i];
if(init(xx, yy) && d[xx][yy] == 1e9 && a[xx][yy] != 'D'){
d[xx][yy] = d[x][y] + 1;
q.push(make_pair(xx, yy));
}
}
}
int l = -1, r = 1e9;
while(l+1 < r){
int m = l+r>>1;
if(good(m)){
l = m;
}
else r = m;
}
cout << l <<"\n";
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
#define name "InvMOD"
if(fopen(name".INP", "r")){
freopen(name".INP","r",stdin);
freopen(name".OUT","w",stdout);
}
int t = 1; //cin >> t;
while(t--) solve();
return 0;
}
