#include <bits/stdc++.h>
using namespace std;
#ifdef _DEBUG
#define dout(x) clog << "Line " << __LINE__ << ": " << #x << "=" << (x) << el
#else
#define dout(x)
#endif
#define mp(a, b) make_pair(a, b)
#define mt(args...) make_tuple(args)
#define pb(x) push_back(x)
#define eb(args...) emplace_back(args)
#define ff first
#define ss second
#define DIE exit(0)
template<typename T>
using vc = vector<T>;
template<typename T>
using uset = unordered_set<T>;
template<typename A, typename B>
using umap = unordered_map<A, B>;
template<typename T, typename Comp>
using pq = std::priority_queue<T, vc<T>, Comp>;
template<typename T>
using maxpq = pq<T, less<T>>;
template<typename T>
using minpq = pq<T, greater<T>>;
using db = double;
using ld = long double;
using ll = long long;
using ull = unsigned long long;
using pi = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vc<int>;
using vll = vc<ll>;
using vpi = vc<pi>;
using vpll = vc<pll>;
using str = string;
constexpr char el = '\n';
constexpr char sp = ' ';
constexpr int inf = 0x3f3f3f3f;
constexpr ll llinf = 0x3f3f3f3f3f3f3f3fLL;
// ---------------------------------------------------------------------
const int N = 805;
int n, s, b[N][N], m[N][N];
int dr[] = {0, 0, -1, 1};
int dc[] = {-1, 1, 0, 0};
char a[N][N];
pi st;
vpi h;
bool good(int r, int c){
return 0 <= r && r < n && 0 <= c && c < n;
}
bool ok(int t){
dout(t);
memset(b, -1, sizeof b);
memset(m, -1, sizeof m);
queue<pi> q;
for(auto x: h){
q.push(x);
b[x.ff][x.ss] = 0;
}
while(!q.empty()){
auto[r, c] = q.front();
if(b[r][c]==t)
break;
q.pop();
for(int i = 0; i < 4; ++i){
int r2 = r + dr[i];
int c2 = c + dc[i];
if(good(r2, c2)&&(a[r2][c2]=='M'||a[r2][c2]=='G')&&b[r2][c2]==-1){
b[r2][c2] = b[r][c] + 1;
q.emplace(r2, c2);
}
}
}
#ifdef _DEBUG
clog << "Line " << __LINE__ << ":\n";
for(int i = 0; i < n; ++i){
for(int j = 0; j < n; ++j)
clog << b[i][j] << sp;
clog << el;
}
clog << el;
#endif
queue<pi> q2; // mecho
q2.push(st);
m[st.ff][st.ss] = 0;
int t2 = t;
while(!q2.empty()){
t2++;
while(!q2.empty()){
auto[r, c] = q2.front();
if(m[r][c]==(t2-t)*s)
break;
q2.pop();
if(~b[r][c])
continue;
for(int i = 0; i < 4; ++i){
int r2 = r + dr[i];
int c2 = c + dc[i];
if(good(r2, c2)&&b[r2][c2]==-1&&m[r2][c2]==-1&&
(a[r2][c2]=='G'||a[r2][c2]=='D')){
if(a[r2][c2]=='D')
return 1;
m[r2][c2] = m[r][c] + 1;
q2.emplace(r2, c2);
}
}
}
#ifdef _DEBUG
clog << "Line " << __LINE__ << ":\n";
for(int i = 0; i < n; ++i){
for(int j = 0; j < n; ++j)
clog << m[i][j] << sp;
clog << el;
}
clog << el;
#endif
while(!q.empty()){
auto[r, c] = q.front();
if(b[r][c]==t2)
break;
q.pop();
for(int i = 0; i < 4; ++i){
int r2 = r + dr[i];
int c2 = c + dc[i];
if(good(r2, c2)&&b[r2][c2]==-1&&(a[r2][c2]=='G'||a[r2][c2]=='M')){
b[r2][c2] = b[r][c] + 1;
q.emplace(r2, c2);
}
}
}
}
return 0;
}
signed main() {
ios::sync_with_stdio(0); cin.tie(0);
cout << fixed; clog << fixed;
#ifdef _DEBUG
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
freopen("debug.txt", "w", stderr);
#endif
cin >> n >> s;
for(int i = 0; i < n; ++i)
for(int j = 0; j < n; ++j){
cin >> a[i][j];
if(a[i][j]=='M')
st = {i, j};
else if(a[i][j]=='H')
h.eb(i, j);
}
#ifdef _DEBUG
clog << "Line " << __LINE__ << ":\n";
for(int i = 0; i < n; ++i){
for(int j = 0; j < n; ++j)
clog << a[i][j];
clog << el;
}
clog << el;
#endif
#ifdef _DEBUG
clog << "Line " << __LINE__ << ":\n";
for(auto[x, y]: h)
clog << x << sp << y << el;
#endif
dout(st.ff);
dout(st.ss);
int ans = -1;
for(int u = int(1e6); u > 0; u /= 2)
while(ans + u <= int(1e6) && ok(ans + u))
ans += u;
cout << ans;
}
