// #pragma GCC target("avx2")
// #pragma GCC optimize("Ofast")
// #pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
#define ll long long
#define cll const ll
#define lp(a, b, c) for(ll a = b; a <= c; ++a)
#define lpd(a, b, c) for(ll a = b; a >= c; --a)
#define vec(a) vector<a>
#define pp(a, b) pair<a, b>
#define EACHCASE lpd(cs, read(), 1)
#define Fname "f"
using namespace std;
template <typename T> inline void Read(T &x){
x = 0; char c;
ll dau = 1;
while(!isdigit(c = getchar())) if(c == '-') dau = -1;
do{
x = x * 10 + c - '0';
} while (isdigit(c = getchar()));
x *= dau;
}
ll read(){
ll tmp;
cin >> tmp;
return tmp;
}
void giuncute(){
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
}
void OF(){
if(fopen(Fname".inp", "r")){
freopen(Fname".inp", "r", stdin);
freopen(Fname".out", "w", stdout);
} else if(fopen(Fname".in", "r")){
freopen(Fname".in", "r", stdin);
freopen(Fname".out", "w", stdout);
}
}
cll mxn = 805, dx[] = {-1, 0, 1, 0}, dy[] = {0, -1, 0, 1};
ll n, s, a[mxn][mxn], d[mxn][mxn], rest[mxn][mxn];
pp(ll, ll) st, fi;
// void bfs(ll i, ll j, ll step, const ll &ti){
// // if(step == s) return;
// // lp(t, 0, 3){
// // ll ii = i + dx[t], jj = j + dy[t];
// // if(a[ii][jj] == -1 || d[ii][jj]) continue;
// // d[ii][jj] = ti;
// // if(a[ii][jj] > ti) q.push({ii, jj});
// // dfs(ii, jj, step + 1, ti);
// // }
// queue<pp(ll, ll)> qq[2];
// qq[0].push({i, j});
// while(qq[0].size()){
// if(++step > s) break;
// while(qq[0].size()){
// ll u = qq[0].front().first, v = qq[0].front().second;
// // if(i == 4 && j == 5) cerr << u << ' ' << v << '\n';
// qq[0].pop();
// lp(t, 0, 3){
// ll nu = u + dx[t], nv = v + dy[t];
// if(a[nu][nv] == -1 || (d[nu][nv] != d[u][v] && d[nu][nv] != 0)) continue;
// d[nu][nv] = d[u][v];
// if(a[nu][nv] > d[nu][nv]) q.push({nu, nv});
// qq[1].push({nu, nv});
// }
// }
// swap(qq[0], qq[1]);
// }
// }
bool check(ll timestart){
lp(i, 1, n) lp(j, 1, n) d[i][j] = rest[i][j] = 0;
d[st.first][st.second] = timestart, rest[st.first][st.second] = s;
queue<pp(ll, ll)> q;
q.push(st);
while(q.size()){
ll u = q.front().first, v = q.front().second;
q.pop();
lp(i, 0, 3){
ll nu = u + dx[i], nv = v + dy[i];
if(a[nu][nv] == -1) continue;
if(d[nu][nv] == d[u][v]){
if(rest[nu][nv] < rest[u][v] - 1){
rest[nu][nv] = rest[u][v] - 1;
q.push({nu, nv});
}
} else if(!d[nu][nv]){
if(rest[u][v] == 1){
if(a[nu][nv] > d[u][v] + 1){
d[nu][nv] = d[u][v] + 1, rest[nu][nv] = s;
q.push({nu, nv});
}
} else{
if(a[nu][nv] > d[u][v]){
d[nu][nv] = d[u][v], rest[nu][nv] = rest[u][v] - 1;
q.push({nu, nv});
}
}
}
}
}
// while(q.size()){
// ll u = q.front().first, v = q.front().second;
// q.pop();
// lp(i, 0, 3){
// ll nu = u + dx[i], nv = v + dy[i];
// if(a[nu][nv] == -1 || (d[nu][nv] != 0 && d[nu][nv] != d[u][v] + 1)) continue;
// d[nu][nv] = d[u][v] + 1;
// // if(u == 4 && v == 4) cerr << nu << ' ' << nv << ' ' << d[nu][nv] << '\n';
// if(a[nu][nv] > d[nu][nv]) q.push({nu, nv});
// bfs(nu, nv, 1, d[nu][nv]);
// }
// }
// lp(i, 1, n){
// lp(j, 1, n) cerr << d[i][j] << ' ';
// cerr << '\n';
// }
if(!d[fi.first][fi.second])
return 0;
return 1;
}
int main(){
giuncute();
#ifndef ONLINE_JUDGE
OF();
#endif
memset(a, -1, sizeof a);
memset(d, -1, sizeof d);
cin >> n >> s;
queue<pp(ll, ll)> q;
lp(i, 1, n) lp(j, 1, n){
char c;
cin >> c;
a[i][j] = 0;
if(c == 'M') st = {i, j};
else if(c == 'D') fi = {i, j};
else if(c == 'T') a[i][j] = -1;
else if(c == 'H') q.push({i, j}), a[i][j] = 1;
}
while(q.size()){
ll u = q.front().first, v = q.front().second;
q.pop();
lp(i, 0, 3){
ll nu = u + dx[i], nv = v + dy[i];
if(a[nu][nv] || (nu == fi.first && nv == fi.second)) continue;
a[nu][nv] = a[u][v] + 1;
q.push({nu, nv});
}
}
a[fi.first][fi.second] = 1e16;
// lp(i, 1, n){
// lp(j, 1, n) cerr << a[i][j] << ' ';
// cerr << '\n';
// }
// cerr << check(2);
ll l = 1, r = a[st.first][st.second] - 1, ans = -1;
while(l <= r){
ll mid = (l + r) >> 1;
if(check(mid)) ans = mid, l = mid + 1;
else r = mid - 1;
}
if(ans != -1) ans -= 1;
cout << ans;
}
