#include<bits/stdc++.h>
#define pii pair<int, int>
#define fi first
#define se second
using namespace std;
const int dx[] = {1, 0, 0, -1};
const int dy[] = {0, 1, -1, 0};
const int MAXN = 8e2 + 10;
const int inf = 1e9 + 7;
int n, s;
int xe, ye;
int grid[MAXN][MAXN];
int loangbee[MAXN][MAXN];
int loangpl[MAXN][MAXN];
bool exceed(int x, int y) {
return (x > n || x < 1 || y > n || y < 1);
}
void bfsbee() {
queue<pair<int, int>> q;
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= n; j++) {
if (grid[i][j] == 4) {
q.push({i, j});
loangbee[i][j] = 0;
}
}
}
while (!q.empty()) {
pii temp = q.front();
q.pop();
int x = temp.fi;
int y = temp.se;
for (int i = 0; i < 4; i++) {
int u = x + dx[i];
int v = y + dy[i];
if (!exceed(u, v)) {
if (loangbee[u][v] == inf && grid[u][v] == 1) {
loangbee[u][v] = loangbee[x][y] + 1;
q.push({u, v});
}
}
}
}
}
int bfspl(int original_value) {
queue<pair<int, int>> q;
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= n; j++) {
if (grid[i][j] == 2) {
q.push({i, j});
loangpl[i][j] = 0;
}
else {
loangpl[i][j] = inf;
}
}
}
while (!q.empty()) {
pii temp = q.front();
q.pop();
int x = temp.fi;
int y = temp.se;
for (int i = 0; i < 4; i++) {
int u = x + dx[i];
int v = y + dy[i];
if (!exceed(u, v)) {
if (loangpl[u][v] == inf && grid[u][v] == 1) {
if ((loangpl[x][y] + 1) / s < loangbee[u][v] - original_value) {
q.push({u, v});
loangpl[u][v] = loangpl[x][y] + 1;
};
}
}
}
}
for (int i = 0; i < 4; i++) {
int u = xe + dx[i];
int v = ye + dy[i];
if (exceed(u, v)) continue;
if (loangpl[u][v] != inf) return 1;
}
return 0;
}
int main() {
cin >> n >> s;
for (int i = 1; i <= n; i++) {
string str;
cin >> str;
for (int j = 1; j <= n; j++) {
char c = str[j-1];
loangpl[i][j] = inf;
loangbee[i][j] = inf;
if (c == 'T') {
grid[i][j] = 0;
}
if (c == 'G') grid[i][j] = 1;
if (c == 'M') grid[i][j] = 2;
if (c == 'D') {
grid[i][j] = 1;
xe = i;
ye = j;
}
if (c == 'H') grid[i][j] = 4;
}
}
bfsbee();
// for (int i = 1; i <= n; i++) {
// for (int j = 1; j <= n; j++) {
// cout << loangbee[i][j] << " ";
// }
// cout << endl;
// }
// cout << "map nguoi" << endl;
// for (int i = 1; i <= n; i++) {
// for (int j = 1; j <= n; j++) {
// cout << loangpl[i][j] << " ";
// }
// cout << endl;
//
int l = 0, r = n * n;
while (l <= r) {
int mid = (l + r) / 2;
if (bfspl(mid) == 1) {
l = mid + 1;
}
else r = mid - 1;
}
cout << l - 1;
return 0;
}
