#include <bits/stdc++.h>
#define f first
#define s second
using ll = long long;
using namespace std;
const int inf = 1<<30;
int bees[800][800];
bool go[800][800];
int bfs[640000][3];
int p1, p2, len;
int ra, rb, rc;
pair<int, int> st, en;
pair<int, int> d4[4] = {{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
int N, S;
void push(int a, int b, int c){
bfs[p2][0] = a;
bfs[p2][1] = b;
bfs[p2][2] = c;
p2++;
if(p2 == 640000) p1 = 0;
len++;
}
void poll(){
ra = bfs[p1][0];
rb = bfs[p1][1];
rc = bfs[p1][2];
p1++;
if(p1 == 640000) p1 = 0;
len--;
}
bool works(int t){
p1 = p2 = len = 0;
push(st.f, st.s, -1);
while(len) {
poll();
for(pair<int, int> a: d4) {
int na = ra+a.f, nb = rb+a.s;
if(na >= 0 && na < N && nb >= 0 && nb < N &&
go[na][nb] && (rc+1)/S < bees[na][nb]-t) {
if(na == en.f && nb == en.s) return 1;
push(na, nb, rc+1);
}
}
}
return 0;
}
int main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
p1 = p2 = len = 0;
cin >> N >> S;
for(int i = 0; i<N; i++) for(int j = 0; j<N; j++) bees[i][j] = inf;
for(int i = 0; i<N; i++) {
string c; cin >> c;
for(int j = 0; j<N; j++) {
go[i][j] = c[j] != 'T';
if(c[j] == 'M') st = {i, j};
if(c[j] == 'D') en = {i, j};
if(c[j] == 'H') {
push(i, j, 0);
bees[i][j] = 0;
}
}
}
while(len) {
poll();
int c = bees[ra][rb];
for(pair<int, int> a: d4) {
pair<int, int> next = {ra+a.f, rb+a.s};
if(next.f >= 0 && next.s >= 0 && next.f < N && next.s < N &&
go[next.f][next.s] && bees[next.f][next.s] == inf && (next.f != en.f || next.s != en.s)) {
bees[next.f][next.s] = c+1;
push(next.f, next.s, 0);
}
}
}
int lo = -1, hi = bees[st.f][st.s];
while (lo < hi) {
int mid = lo + (hi - lo + 1) / 2;
if (works(mid)) lo = mid;
else hi = mid - 1;
}
cout << lo;
}
