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*/
#include <bits/stdc++.h>
#define input ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define endl '\n'
#define fi first
#define se second
#define eb emplace_back
#define pb push_back
#define ce cout << endl
#define FOR(i, l, r) for (int i = l; i <= r; i++)
#define FOR2(i, l, r) for (int i = l; i >= r; i--)
using namespace std;
using ll = long long;
using str = string;
using pll = pair<ll, ll>;
using pii = pair<int, int>;
const ll N = 1e5+1;
const ll LOGN = 19;
const int INF = numeric_limits<int>::max();
const ll MOD = 998244353;
int dx[] = {1, -1, 0, 0};
int dy[] = {0, 0, 1, -1};
char op[] = {'D','U','R','L'};
void solve() {
int n , s;
cin >> n >> s;
vector<vector<char>> matrix(n,vector<char>(n));
vector<pii> hives;
pii mecho;
pii end;
FOR(i,0,n-1){
FOR(j,0,n-1)
{
cin >> matrix[i][j];
if(matrix[i][j] == 'H') hives.pb({i,j});
else if(matrix[i][j] == 'M') mecho ={i,j};
else if(matrix[i][j] == 'D') end = {i,j};
}
}
function<bool(int,int)> inside =[&] (int i ,int j){
return (i > - 1 && i < n && j > -1 && j < n && matrix[i][j] != 'T' && matrix[i][j] != 'H' && matrix[i][j] != 'D' );
};
function<bool(int,int)> check =[&] (int time,int dist){
return time / s < dist;
};
deque<pii> q;
vector<vector<int>> bee_time(n,vector<int>(n,-1));
for(auto &i : hives){
q.pb(i);
bee_time[i.fi][i.se] = 0;
}
while(!q.empty()){
pii c = q.front();
q.pop_front();
for(int i = 0 ; i < 4 ; i++){
int x = c.fi + dx[i] , y = c.se + dy[i];
if(inside(x,y) && bee_time[x][y] == -1){
bee_time[x][y] = bee_time[c.fi][c.se] + 1;
q.pb({x,y});
}
}
}
int l = -1 ;
int h = n * n;
while( l < h){
int m = l + h + 1 >> 1;
vector<vector<int>> mecho_time(n,vector<int>(n,INF));
q.pb(mecho);
mecho_time[mecho.fi][mecho.se] = 0;
if(bee_time[mecho.fi][mecho.se] <= m) q.pop_front();
while(!q.empty()){
pii c = q.front();
q.pop_front();
for(int i = 0 ; i < 4 ; i ++){
int x = c.fi + dx[i] , y = c.se + dy[i];
if(inside(x,y) && mecho_time[c.fi][c.se] < mecho_time[x][y] &&check(mecho_time[c.fi][c.se] + 1,bee_time[x][y] - m)){
mecho_time[x][y] = mecho_time[c.fi][c.se] + 1;
q.pb({x,y});
}
}
}
bool reached = false;
for(int i = 0 ; i < 4 ; i ++){
int x = end.fi + dx[i],y = end.se + dy[i];
if(inside(x,y) && check(mecho_time[x][y] , bee_time[x][y] - m)){
reached = true;
}
}
if(reached) l = m;
else h = m - 1;
}
cout << l <<endl;
}
int main() {
input
const bool cap = true;
if (cap)
solve();
else {
ll t;
cin >> t;
while (t--) solve();
}
}
