#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pi pair<int, int>
#define ti tuple<ll, int, int>
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define int ll
vector<vector<char>> grid;
vector<vector<ll>> t;
vector<pi> direction={{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
int n;
ll s;
int si=-1, sj=-1;
bool bfs(ll mid) {
vector<vector<bool>> visited(n, vector<bool>(n));
queue<ti> nq;
if(mid<t[si][sj]) nq.push({s*mid, si, sj});
else return false;
visited[si][sj]=true;
while(nq.size()) {
auto [cnt, i, j]=nq.front(); nq.pop();
if(grid[i][j]=='D') return true;
for(auto &[di, dj]: direction) {
int ni=i+di;
int nj=j+dj;
if(ni>=0 && nj>=0 && ni<n && nj<n && (t[ni][nj]==LLONG_MAX || (ll)(cnt+1)<1LL*s*t[ni][nj]) && grid[ni][nj]!='T' && !visited[ni][nj]) {
visited[ni][nj]=true;
nq.push({cnt+1, ni, nj});
}
}
}
return false;
}
int32_t main() {
ios::sync_with_stdio(false);
cin.tie(0);
cin >> n >> s;
grid.resize(n, vector<char>(n));
t.resize(n, vector<ll>(n, LLONG_MAX));
queue<ti> q;
for(int i=0; i<n; i++) {
for(int j=0; j<n; j++) {
cin >> grid[i][j];
if(grid[i][j]=='H') {
q.push({0, i, j});
t[i][j]=0;
// visited[i][j]
} else if(grid[i][j]=='M') {
si=i;
sj=j;
}
}
}
while(q.size()) {
auto [cnt, i, j]=q.front(); q.pop();
for(auto &[di, dj]: direction) {
int ni=i+di;
int nj=j+dj;
if(ni>=0 && nj>=0 && ni<n && nj<n && t[ni][nj]==LLONG_MAX && (grid[ni][nj]!='T' && grid[ni][nj]!='D')) {
t[ni][nj]=cnt+1;
q.push({cnt+1, ni, nj});
}
}
}
// for (int i = 0; i < n; i++) {
// for (int j = 0; j < n; j++) cout << (t[i][j] == LLONG_MAX ? -1 : t[i][j]) << ' ';
// cout << '\n';
// }
ll l=-1, r=1e9;
while(l<r) {
ll mid=(l+r+1)/2;
if(bfs(mid)) {
l=mid;
} else {
r=mid-1;
}
}
cout << (l<INT_MAX ? l:-1);
return 0;
}
