#include <bits/stdc++.h>
#define lli long long
#define ld long double
#define tmt angel
using namespace std;
const int maxn = 802;
int vis[maxn][maxn], n, m;
char a[maxn][maxn];
int tim[maxn][maxn];
int mtim[maxn][maxn];
int hi, hj, sti, stj;
int x[4] = {1, -1, 0, 0};
int y[4] = {0, 0, 1, -1};
deque<pair<pair<int, int>, int>> s;
bool flag = false;
int bvis[maxn][maxn];
bool valid_sq(int nx, int ny) {
return nx >= 0 && nx < n && ny >= 0 && ny < n &&
(a[nx][ny] == 'G' || a[nx][ny] == 'M');
}
void gocheck(int i, int j, int cost)
{
if(i < 1 || j < 1 || i > n || j > n || bvis[i][j] == 1 || a[i][j] == 'D' || a[i][j] == 'T') return;
bvis[i][j] = 1;
tim[i][j] = cost;
s.push_back({{i, j}, cost});
}
void spread(int i, int j, int cost, int st)
{
//if(vis[hi][hj] == 1) return;
if(i < 1 || j < 1 || i > n || j > n || vis[i][j] == 1) return;
if(tim[i][j] - st > cost / m)
{
s.push_back({{i, j}, cost});
vis[i][j] = 1;
mtim[i][j] = cost;
}
}
void Bfs()
{
while(!s.empty())
{
int i = s.front().first.first;
int j = s.front().first.second;
int c = s.front().second;
s.pop_front();
for(int f = 0; f < 4; f++)
{
gocheck(i + x[f], j + y[f], c+1);
}
}
}
bool checked(int st)
{
for(int i = 1; i <= n; i++)
{
for(int j = 1; j <= n; j++)
{
vis[i][j] = a[i][j] == 'G' || a[i][j] == 'D' ? 0 : 1;
mtim[i][j] = 0;
}
}
s.clear();
s.push_back({{sti, stj}, 0});
while(!s.empty())
{
int i = s.front().first.first;
int j = s.front().first.second;
int c = s.front().second;
s.pop_front();
for(int f = 0; f < 4; f++)
{
spread(i + x[f], j + y[f], c+1, st);
//if(vis[hi][hj] == 1) break;
}
}
// if(st == 0) s.push_back({ {sti, stj},{2, 0} });
for(int f = 0; f < 4; f++)
{
int nx = hi + x[f], ny = hj + y[f];
if(valid_sq(nx, ny) && vis[nx][ny] == 1 && mtim[nx][ny] / m < tim[nx][ny] - st) return true;
}
return false;
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
// freopen(".INP", "r" , stdin);
// freopen(".OUT", "w" , stdout);
cin >> n >> m;
for(int i = 1; i <= n; i++)
{
for(int j = 1; j <= n; j++)
{
cin >> a[i][j];
if(a[i][j] == 'M' )
{
vis[i][j] = 1;
sti = i;
stj = j;
}
else vis[i][j] = a[i][j] == 'G' || a[i][j] == 'D' ? 0 : 1;
if(a[i][j] == 'D')
{
hi = i;
hj = j;
}
if(a[i][j] == 'H')
{
s.push_back({{i, j}, 0});
bvis[i][j] = 1;
}
}
}
Bfs();
//s.clear();
//cout << checked(1);
int low = 0, high = n*n, mid;
while(low <= high)
{
mid = (low + high) / 2;
if(tim[sti][stj] <= mid) high = mid-1;
if(checked(mid)) low = mid +1;
else high = mid - 1;
}
cout << low-1;
/*for(int i = 1; i <= n; i++)
{
for(int j = 1; j <= n; j++)
{
cout << mtim[i][j] << " ";
}
cout << '\n';
}
cout << '\n';
for(int i = 1; i <= n; i++)
{
for(int j = 1; j <= n; j++)
{
cout << tim[i][j] << " ";
}
cout << '\n';
}*/
return 0;
}
