#include<bits/stdc++.h>
#define int long long
using namespace std;
int n, s, disH[1010][1010], dis[1010][1010], xx[] = {0, 0, -1, 1}, xy[] = {-1, 1, 0, 0};
char mp[1010][1010];
queue<tuple<int, int, int>> q;
bool solve(int mid){
for(int i = 1; i <= n; ++i){
for(int j = 1; j <= n; ++j){
if(mp[i][j] == 'M') q.emplace(i, j, mid*s), dis[i][j] = mid*s;
else dis[i][j] = 1e18;
}
}
while(!q.empty()){
int x = get<0>(q.front()), y = get<1>(q.front()), w = get<2>(q.front()); q.pop();
if(dis[x][y] < w || dis[x][y] >= disH[x][y]) continue;
if(mp[x][y] == 'D') return true;
for(int i = 0; i < 4; ++i){
int nx = x + xx[i];
int ny = y + xy[i];
if(nx < 1 || nx > n || ny < 1 || ny > n || mp[nx][ny] == 'T') continue;
if(dis[nx][ny] > w + 1){
dis[nx][ny] = w + 1;
q.emplace(nx, ny, w + 1);
}
}
}
return false;
}
int32_t main(){
cin.tie(nullptr)->sync_with_stdio(false);
cin >> n >> s;
for(int i = 1; i<=n; ++i) for(int j = 1; j <= n; ++j) cin >> mp[i][j];
for(int i = 1; i <= n; ++i){
for(int j = 1; j <=n; ++j){
if(mp[i][j] == 'H') q.emplace(i, j, 0), disH[i][j] = 0;
else disH[i][j] = 1e18;
}
}
while(!q.empty()){
int x = get<0>(q.front()), y = get<1>(q.front()), w = get<2>(q.front()); q.pop();
if(disH[x][y] < w) continue;
for(int i = 0; i < 4; ++i){
int nx = x + xx[i];
int ny = y + xy[i];
if(nx < 1 || nx > n || ny < 1 || ny > n || mp[nx][ny] == 'T') continue;
if(disH[nx][ny] > w + 1){
disH[nx][ny] = w + 1;
q.emplace(nx, ny, w + 1);
}
}
}
for(int i = 1; i <= n; ++i) for(int j = 1; j <= n; ++j) disH[i][j] == 1e18 ? disH[i][j] *= 1 : disH[i][j] *= s;
int l = 0, r = 1e18, ans = -1;
//for(int i = 1; i <= n; ++i) for(int j = 1; j <= n; ++j) cout << i << ' ' << j << ' ' << disH[i][j] << '\n';
while(l <= r){
int mid = (l + r) >> 1;
if(solve(mid)) ans = mid, l = mid + 1;
else r = mid - 1;
}
cout << ans;
}
