//Nguyen Huu Hoang Minh
#include <bits/stdc++.h>
#define sz(x) int(x.size())
#define all(x) x.begin(),x.end()
#define reset(x) memset(x, 0,sizeof(x))
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define N 805
#define remain(x) if (x > MOD) x -= MOD
#define ii pair<int, int>
#define iiii pair< ii , ii >
#define viiii vector< iiii >
#define vi vector<int>
#define vii vector< ii >
#define bit(x, i) (((x) >> (i)) & 1)
#define Task "test"
#define int long long
using namespace std;
typedef long double ld;
const int inf = 1e10;
const int minf = -1e10;
int n, s;
char a[N][N];
ii M, D;
vector<ii> bee;
void readfile()
{
ios_base::sync_with_stdio(false);
cin.tie(0);cout.tie(0);
if (fopen(Task".inp","r"))
{
freopen(Task".inp","r",stdin);
//freopen(Task".out","w",stdout);
}
cin >> n >> s;
for(int i=1; i<=n; i++){
for(int j=1; j<=n; j++){
cin >> a[i][j];
if (a[i][j]=='M') M = ii(i,j);
if (a[i][j]=='D') D = ii(i,j);
if (a[i][j]=='H') bee.pb(ii(i,j));
}
}
}
int d[N][N];
int dm[N][N];
int dx[4] = {1,-1,0,0};
int dy[4] = {0,0,1,-1};
bool ok(int x, int y){
if (1 <= x && x <= n && 1 <= y && y <= n) return true;
return false;
}
void build_bee(){
queue<ii> q;
memset(d, -1, sizeof d);
for(ii x : bee){
d[x.fi][x.se]=0;
q.push(ii(x.fi,x.se));
}
while (q.size()){
int u = q.front().fi;
int v = q.front().se;
//cout << u << ' ' << v << ' ' << d[u][v] << endl;
q.pop();
for(int i=0; i<4; i++){
int x = u + dx[i];
int y = v + dy[i];
if (d[x][y]==-1 && ok(x,y) && (a[x][y]=='G'||a[x][y]=='M')){
d[x][y] = d[u][v] + s;
q.push(ii(x,y));
}
}
}
d[D.fi][D.se] = 1e18;
}
bool can_eat(int ti){
if (ti*s >= d[M.fi][M.se]) return false;
queue<ii> q;
memset(dm, -1, sizeof dm);
dm[M.fi][M.se] = ti*s;
q.push(ii(M.fi,M.se));
while (q.size()){
int u = q.front().fi;
int v = q.front().se;
q.pop();
for(int i=0; i<4; i++){
int x = u + dx[i];
int y = v + dy[i];
if (!ok(x,y) || a[x][y]=='T' || a[x][y]=='H') continue;
if (dm[x][y]==-1){
dm[x][y] = dm[u][v] + 1;
if (dm[x][y] < d[x][y]){
q.push(ii(x,y));
}
}
}
}
return (dm[D.fi][D.se]!=-1);
}
void proc()
{
build_bee();
int l = 0, r = 1e9, ans=-1;
while (r-l > 0){
int mid = (l+r)/2;
if (can_eat(mid)){
l = mid+1;
ans = mid;
}
else r = mid;
}
cout << ans;
}
signed main()
{
readfile();
proc();
return 0;
}
