#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
#include <unordered_map>
#include <unordered_set>
#define ll int
#define ld long double
#define pl pair<ll, ll>
#define vi vector<ll>
#define vii vector<vi>
#define vc vector<char>
#define vcc vector<vc>
#define vp vector<pl>
#define mi map<ll,ll>
#define mc map<char,int>
#define sortx(X) sort(X.begin(),X.end());
#define all(X) X.begin(),X.end()
#define allr(X) X.rbegin(),X.rend()
#define ln '\n'
#define YES {cout << "YES\n"; return;}
#define NO {cout << "NO\n"; return;}
#define MUN {cout << "-1\n"; return;}
const int MODE = 998244353;
using namespace std;
unordered_map<int, int> MC;
int ST(vi &X) {
int re = 0;
for (auto a : X) {
re *= 10;
re += a;
}
auto it = MC.find(re);
if (it == MC.end()) {
MC[re] = MC.size();
return MC.size()-1;
}
return it->second;
}
const int SZ = 362990;
vp dd = {{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
void solve(int tc) {
ll n, s; cin >> n >> s;
vcc X(n + 10, vc(n + 10, 'T'));
vii ds2(n + 10, vi(n + 10, INT32_MAX));
queue<pl> q2;
pl en, st;
for (int i = 1; i <= n; i++)
for (int j = 1; j <= n; j++) {
cin >> X[i][j];
if (X[i][j] == 'M') {
st = {i, j};
}
if (X[i][j] == 'H') {
ds2[i][j] = 0;
q2.push({i, j});
}
if (X[i][j] == 'D') en = {i, j};
}
while (!q2.empty()) {
pl tp = q2.front();
q2.pop();
for (auto [x,y] : dd) {
ll a = x + tp.first;
ll b = y + tp.second;
ll w = 1 + ds2[tp.first][tp.second];
if (ds2[a][b] > w && (X[a][b] == 'G')) {
ds2[a][b]=w;
q2.push({a, b});
}
}
}
ll sol = -1;
ll l = 0, r = n * n;
while (l <= r)
{
ll mid = (l + r) / 2;
vii dp(n + 10, vi(n + 1, INT32_MAX));
dp[st.first][st.second] = 0;
queue<pl> q;
q.push(st);
while (!q.empty())
{
pl tp = q.front();
q.pop();
ll v = dp[tp.first][tp.second];
for (auto [x,y] : dd) {
ll a = x + tp.first;
ll b = y + tp.second;
ll w = mid + (v + 1) / s + 1;
bool ls = (v % s == 0);
if (ds2[a][b] >= w && dp[a][b] > v + 1 && (X[a][b] == 'G' || X[a][b] == 'D')) {
dp[a][b] = v + 1;
q.push({a, b});
}
}
}
if (dp[en.first][en.second] != INT32_MAX) sol = mid, l = mid + 1;
else r = mid - 1;
}
cout << sol << '\n';
}
int main()
{
ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
int size = 1;
// freopen("atlarge.in", "r", stdin);
// freopen("atlarge.out", "w", stdout);
// cin >> size;
for (int i = 1; i <= size; i++)
solve(i);
}
