#include <bits/stdc++.h>
using namespace std;
char t[1024][1024];
char test[1024][1024];
int dist[1024][1024];
int n, s;
class state{
public:
int x,y,cw;
state(int a, int b, int c): x(a), y(b), cw(c) {}
};
void propagateBees(queue<state>& q, int limit){
while(!q.empty() && q.front().cw < limit){
state cur = q.front();
q.pop();
int x = cur.x;
int y = cur.y;
int w = cur.cw+1;
if(x > 1 && (test[x-1][y] == 'G' && dist[x-1][y] > w) || test[x-1][y] == 'M'){
dist[x-1][y] = w;
test[x-1][y] = 'H';
q.emplace(x-1, y, w);
}
if(x < n && (test[x+1][y] == 'G' && dist[x+1][y] > w) || test[x+1][y] == 'M'){
dist[x+1][y] = w;
test[x+1][y] = 'H';
q.emplace(x+1, y, w);
}
if(y > 1 && (test[x][y-1] == 'G' && dist[x][y-1] > w) || test[x][y-1] == 'M'){
dist[x][y-1] = w;
test[x][y-1] = 'H';
q.emplace(x, y-1, w);
}
if(y < n && (test[x][y+1] == 'G' && dist[x][y+1] > w) || test[x][y+1] == 'M'){
dist[x][y+1] = w;
test[x][y+1] = 'H';
q.emplace(x, y+1, w);
}
}
}
void propagateMecho(queue<state>& q, int limit){
while(!q.empty() && q.front().cw < limit){
state cur = q.front();
q.pop();
int x = cur.x;
int y = cur.y;
if(test[x][y] != 'M') continue;
int w = cur.cw+1;
if(x > 1 && (test[x-1][y] == 'G' || test[x-1][y] == 'D') && dist[x-1][y] > w){
dist[x-1][y] = w;
test[x-1][y] = 'M';
q.emplace(x-1, y, w);
}
if(x < n && (test[x+1][y] == 'G' || test[x+1][y] == 'D') && dist[x+1][y] > w){
dist[x+1][y] = w;
test[x+1][y] = 'M';
q.emplace(x+1, y, w);
}
if(y > 1 && (test[x][y-1] == 'G' || test[x][y-1] == 'D') && dist[x][y-1] > w){
dist[x][y-1] = w;
test[x][y-1] = 'M';
q.emplace(x, y-1, w);
}
if(y < n && (test[x][y+1] == 'G' || test[x][y+1] == 'D') && dist[x][y+1] > w){
dist[x][y+1] = w;
test[x][y+1] = 'M';
q.emplace(x, y+1, w);
}
}
}
bool escapePossible(int days){
if(days == -1) return true;
queue<state> q, mq;
int dx, dy;
for(int i = 1; i <= n; i++){
for(int j = 1; j <= n; j++){
test[i][j] = t[i][j];
dist[i][j] = 1e9;
if(t[i][j] == 'H'){
q.emplace(i,j,0);
dist[i][j] = 0;
}else if(t[i][j] == 'D'){
dx = i;
dy = j;
}else if(t[i][j] == 'M'){
mq.emplace(i,j,0);
dist[i][j] = 0;
}
}
}
propagateBees(q, days);
int lm = 0;
while(!q.empty() || !mq.empty()){
lm += s;
propagateMecho(mq, lm);
if(test[dx][dy] == 'M') return true;
days++;
propagateBees(q, days);
}
return false;
}
int main(){
scanf("%d%d",&n,&s);
for(int i = 1; i <= n; i++){
scanf("%s", t[i]+1);
}
int lo = -1;
int hi = n*n;
int mid;
while(lo < hi){
mid = (lo+hi+1)/2;
if(escapePossible(mid)){
lo = mid;
}else{
hi = mid-1;
}
}
printf("%d\n", lo);
return 0;
}
