#include<bits/stdc++.h>
using namespace std;
// define
#define execute cerr << " Time: " << fixed << setprecision(6) << (1.0 * clock() / CLOCKS_PER_SEC) << "s\n";
#define ll long long
#define ii pair <int , int>
#define iii pair <int , ii>
#define se second
#define fi first
#define all(v) (v).begin() , (v).end()
#define Unique(v) sort(all(v)) , v.resize(unique(all(v)) - v.begin())
#define bit(x,i) (((x) >> (i)) & 1LL)
#define flip(x,i) ((x) ^ (1LL << (i)))
#define ms(d,x) memset(d , x , sizeof(d))
#define exist __exist
#define ends __ends
#define visit visited
#define left __left
#define right __right
#define prev __prev
#define next __next
#define sitingfake 1
#define orz 1
//constant
const long long mod = 1e9 + 7;
const long long linf = 4557430888798830399LL;
const long long nlinf = -4485090715960753727LL;
const int inf = 1061109567;
const int ninf = -1044266559;
const int dx[] = {0 , -1 , 0 , 1};
const int dy[] = {-1 , 0 , 1 , 0};
template<typename T> bool maximize(T &a, const T &b)
{
if(a < b) {a = b; return 1;}
return 0;
}
template<typename T> bool minimize(T &a, const T &b)
{
if(a > b) {a = b; return 1;}
return 0;
}
void Plus(ll & a ,ll b)
{
b %= mod;
a += b;
if(a < 0) a += mod;
a %= mod;
return;
}
void Mul(ll & a, ll b)
{
(a *= (b % mod)) %= mod;
return;
}
//code
const int maxn = 808;
char a[maxn][maxn];
ii st , fin;
int n , S;
vector <ii> Bee;
int distBee[maxn][maxn];
int dist[maxn][maxn];
bool check(int eat)
{
for(int i = 1; i <= n; i++)
{
for(int j = 1; j <= n; j++)
{
dist[i][j] = inf;
}
}
queue <ii> q;
dist[st.fi][st.se] = 0;
q.push(st);
while(!q.empty())
{
int u = q.front().fi;
int v = q.front().se;
//cout << u << " " << v << endl;
q.pop();
for(int i = 0 ; i < 4; i++)
{
int x = u + dx[i];
int y = v + dy[i];
if(1 <= x && x <= n && 1 <= y && y <= n && a[x][y] != 'T')
{
if(((dist[u][v] + 1) / S) < distBee[x][y] - eat && minimize(dist[x][y] , dist[u][v] + 1))
{
q.push({x , y});
}
}
}
}
for(int i = 0; i < 4; i++)
{
int u = dx[i] + fin.fi;
int v = dy[i] + fin.se;
if(1 <= u && u <= n && 1 <= v && v <= n && a[u][v] != 'T' && dist[u][v] != inf)
{
return 1;
}
}
return 0;
}
void solve(void)
{
cin >> n >> S;
for(int i = 1; i <= n; i++)
{
for(int j = 1; j <= n; j++)
{
cin >> a[i][j];
if(a[i][j] == 'M') st = ii(i , j);
else if(a[i][j] == 'D') fin = ii(i , j);
else if(a[i][j] == 'H') Bee.push_back({i , j});
}
}
ms(distBee , 0x3f);
queue <ii> q;
for(ii i : Bee) distBee[i.fi][i.se] = 0 , q.push(i);
while(!q.empty())
{
int u = q.front().fi;
int v = q.front().se;
q.pop();
for(int i = 0; i < 4; i++)
{
int x = u + dx[i];
int y = v + dy[i];
if(1 <= x && x <= n && 1 <= y && y <= n && a[x][y] != 'T' && a[x][y] != 'D')
{
if(minimize(distBee[x][y] , distBee[u][v] + 1))
{
q.push({x , y});
}
}
}
}
int left = 0 , right = distBee[st.fi][st.se] - 1 ,ans = -1;
while(left <= right)
{
int mid = (left + right) >> 1;
if(check(mid))
{
ans = mid;
left = mid + 1;
}
else right = mid - 1;
}
cout << ans;
}
/**
**/
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
#define task ""
if(fopen(task".inp","r"))
{
freopen(task".inp","r",stdin);
freopen(task".out","w",stdout);
}
int tc = 1;
// cin >> tc;
while(tc--) solve();
// execute;
}
