#ifndef _Alignof
#define _Alignof(x) __alignof__(x)
#endif
#include<bits/stdc++.h>
#include<ext/pb_ds/tree_policy.hpp>
#include<ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
#define vll vector<long long>
#define vpll vector< pair<long long int , long long int > >
#define rep(i,x,a) for (long long i=x; i<a; i++)
#define si(x) (long long int)x.size()
#define pb push_back
#define ff first
#define ss second
#define lg2(x) (long long int)log2(x)
#define gap " "
#define nl '\n'
#define all(x) (x).begin(),(x).end()
#define no cout<<"No\n"
#define yes cout<<"Yes\n"
#define vld vector<long double>
typedef long long ll;
typedef unsigned long long ull;
typedef long double lld;
#ifndef ONLINE_JUDGE
#define debug(x) cerr << #x <<" "; _print(x); cerr << endl;
#else
#define debug(x)
#endif
void _print(ll t) {cerr << t;}
void _print(int t) {cerr << t;}
void _print(string t) {cerr << t;}
void _print(char t) {cerr << t;}
void _print(lld t) {cerr << t;}
void _print(double t) {cerr << t;}
void _print(ull t) {cerr << t;}
void print(){
cout << '\n';
}
template<class T, class... Ts>
void print(const T& a, const Ts&... b){
cout << a;
(cout << ... << (cout << ' ', b));
cout << '\n';
}
template<class... T>
void input(T&... a){
(cin >> ... >> a);
}
template <class T, class V> void _print(pair <T, V> p);
template <class T> void _print(vector <T> v);
template <class T> void _print(set <T> v);
template <class T, class V> void _print(map <T, V> v);
template <class T> void _print(multiset <T> v);
template <class T, class V> void _print(pair <T, V> p) {cerr << "{"; _print(p.ff); cerr << ","; _print(p.ss); cerr << "}";}
template <class T> void _print(vector <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T> void _print(set <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T> void _print(multiset <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void _print(map <T, V> v) {cerr << "[ "; for (auto i : v) {_print(i); cerr << " ";} cerr << "]";}
template<typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
const int MOD=1e9+7;
const int N=1e6+10;;
const ll INF=1e16;
const long long int LINF=LLONG_MAX;
/*------------------------------------*/
void solve(int tc = 0)
{
ll n,s;input(n,s);
vector<vector<char>> grid(n,vector<char>(n));
for(int i=0;i<n;i++){
for(int j=0;j<n;j++){
cin >> grid[i][j];
}
}
vector<vector<ll>> dis(n,vll(n,INF));
queue<pair<ll,ll>> q;
vll dx = {0,0,1,-1};
vll dy = {1,-1,0,0};
ll xd = 0,yd = 0;
ll xm = 0,ym = 0;
rep(i,0,n)rep(j,0,n)if(grid[i][j]=='M')xm = i,ym = j;
rep(i,0,n)rep(j,0,n)if(grid[i][j]=='D')xd = i,yd = j;
rep(i,0,n)rep(j,0,n)if(grid[i][j]=='H')dis[i][j] = 0,q.push({i,j});
while(!q.empty()){
auto [x,y] = q.front();
q.pop();
for(int i=0;i<4;i++){
ll newx = x+dx[i];
ll newy = y+dy[i];
if(newx >= 0 && newy >=0 && newx < n && newy < n && dis[newx][newy] > dis[x][y]+1 && grid[newx][newy]!='T' && grid[newx][newy]!='D'){
dis[newx][newy] = dis[x][y]+1;
q.push({newx,newy});
}
}
}
auto check = [&](ll mid)->bool{
vector<vector<ll>> mecho(n,vll(n,INF));
if(dis[xm][ym] <= mid){
return false;
}
mecho[xm][ym] = mid;
queue<array<ll,3>>q;q.push({xm,ym,0});
while(!q.empty()){
auto [x,y,step] = q.front();
q.pop();step++;
if(x==xd && y==yd){
return true;
}
for(int i=0;i<4;i++){
ll newx = x+dx[i];
ll newy = y+dy[i];
if(newx >= 0 && newy >= 0 && newx < n && newy < n && grid[newx][newy]!='T' && grid[newx][newy]!='H' && mecho[newx][newy]>mecho[x][y]+(step%s==0) && mecho[x][y]+(step%s==0) < dis[newx][newy]){
mecho[newx][newy] = mecho[x][y]+(step%s==0);
q.push({newx,newy,step});
}
}
}
return false;
};
ll low = 0;
ll high = INF;
ll ans = -1;
while(low <= high){
ll mid = (low+high)/2;
if(check(mid)){
ans = max(ans,mid);
low = mid+1;
}
else{
high = mid-1;
}
}
cout << ans << nl;
}
/*------------------------------------*/
int main()
{
#ifndef ONLINE_JUDGE
freopen("Error.txt","w",stderr);
#endif
ios_base::sync_with_stdio(false);
cin.tie(nullptr); cout.tie(nullptr);
ll tc=1;
for(int i=0 ; i < tc ; i++)
{
solve(i);
}
return 0;
}
