//#pragma GCC optimize("O3,unroll-loops,Ofast") //#pragma GCC target("avx2,bmi,bmi2,popcnt,lzcnt") #include <bits/stdc++.h> // #include <ext/pb_ds/assoc_container.hpp> // #include <ext/pb_ds/tree_policy.hpp> using namespace std; // using namespace __gnu_pbds; #define MAX 200005 #define pb push_back // #define mp make_pair // #define int long long #define f first #define s second #define vi vector<int> #define pii pair<int,int> #define si set<int> #define vpii vector<pair<int,int>> const int mod = 1e9+7; const double INF = 1e9; // myMap.begin()->first : key // myMap.begin()->second : value int epow(int a,int b){int ans=1;while(b){if(b&1) ans*=a;a*=a;b>>=1;ans%=mod;a%=mod;}return ans%mod;} int gcd(int a,int b) {if(a<b)swap(a,b);while(b){int tmp=b;b=a%b;a=tmp;}return a;} int mul(int a,int b){return ((a%mod)*(b%mod))%mod;} int sum(int a,int b){return ((a%mod)+(b%mod))%mod;} //typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update>ordered_set; // typedef // tree<int,null_type,less_equal<int>,rb_tree_tag,tree_order_statistics_node_update>ordered_multiset; int dx[]={1,0,-1,0}; int dy[]={0,1,0,-1}; vector<vector<char>> grid(805,vector<char>(805)); vector<vi> d(805,vi(805,INF)); int n,S; bool valid(int x,int y){ if(x<=0 || y<=0 || x>n || y>n || grid[x][y]=='T') return false; return true; } void solve(){ cin>>n>>S; pii start,end; vpii hives; for(int i=1;i<=n;i++){ for(int j=1;j<=n;j++){ cin>>grid[i][j]; if(grid[i][j]=='M') start={i,j},grid[i][j]='G'; if(grid[i][j]=='D') end={i,j}; if(grid[i][j]=='H') hives.pb({i,j}); } } queue<pii> q; for(auto u : hives) q.push({u.f,u.s}),d[u.f][u.s]=0; while(q.size()){ pii node=q.front(); q.pop(); for(int i=0;i<4;i++){ int x=node.f+dx[i], y=node.s+dy[i]; if(!valid(x,y) || grid[x][y]!='G' || d[x][y]!=INF) continue; d[x][y]=d[node.f][node.s]+1; q.push({x,y}); } } // for(int i=1;i<=n;i++){ // for(int j=1;j<=n;j++) cout<<d[i][j]<<" ";cout<<endl; // } int l=0,r=650000,sayac; while(l<=r){ int mid=(l+r)>>1; vector<vi> dist(n+5,vi(n+5,INF)); q=queue<pii>(); q.push(start); dist[start.f][start.s]=0; while(q.size()){ pii node=q.front(); q.pop(); for(int i=0;i<4;i++){ int x=node.f+dx[i], y=node.s+dy[i]; if(!valid(x,y) || grid[x][y]!='G' || dist[x][y]!=INF) continue; int timer=(dist[node.f][node.s]+1)/S+mid; if( timer>=d[x][y] ) continue; dist[x][y]=dist[node.f][node.s]+1; q.push({x,y}); } } bool flag=false; for(int i=0;i<4;i++){ int x=end.f+dx[i], y=end.s+dy[i]; if(dist[x][y]!=INF) flag=1; } if(flag) l=mid+1,sayac++; else r=mid-1; } if(sayac && r<=640000) cout<<r<<endl; else cout<<"-1\n"; } int32_t main(/*int32_t argc, char* argv[]*/){ std::ios_base::sync_with_stdio(0); std::cin.tie(0); // freopen("atlarge.in", "r", stdin); // freopen("atlarge.out", "w", stdout); int t=1; // cin >> t; while (t--) solve(); return 0; }