#include <bits/stdc++.h>
using namespace std;
using pii = pair<int, int>;
#define X first
#define Y second
const int N = 905, INF = int(1e9);
int n, C, rn[N][N], cn[N][N], rh, ch, rm, cm, cnt, d[2 * N * N], r = INF;
char b[N][N];
vector<pii> e[2 * N * N];
priority_queue<pii, vector<pii>, greater<pii>> pq;
int main(){
scanf("%d", &n);
C = N * N;
for(int i = 1; i <= n; i++) scanf("%s", b[i] + 1);
for(int i = 1; i <= n; i++){
int lst = -1, cur = 1;
for(int j = 1; j <= n; j++){
if(b[i][j] == 'W') cur++;
else{
if(cur){
cnt++;
e[cnt].push_back({cnt + C, 0});
if(lst > 0){
e[lst + C].push_back({cnt, cur * cur});
e[cnt + C].push_back({lst, cur * cur});
}
cur = 0;
lst = cnt;
}
if(b[i][j] == 'H') rh = cnt;
else if(b[i][j] == 'M') rm = cnt;
rn[i][j] = cnt;
}
}
}
for(int i = 1; i <= n; i++){
int lst = -1, cur = 1;
for(int j = 1; j <= n; j++){
if(b[j][i] == 'W') cur++;
else{
if(cur){
cnt++;
e[cnt].push_back({cnt + C, 0});
if(lst > 0){
e[lst + C].push_back({cnt, cur * cur});
e[cnt + C].push_back({lst, cur * cur});
}
cur = 0;
lst = cnt;
}
if(b[j][i] == 'H') ch = cnt;
else if(b[j][i] == 'M') cm = cnt;
cn[j][i] = cnt;
}
}
}
for(int i = 1; i <= n; i++){
for(int j = 1; j <= n; j++){
if(rn[i][j] && cn[i][j]){
e[rn[i][j]].push_back({cn[i][j] + C, 0});
e[cn[i][j]].push_back({rn[i][j] + C, 0});
}
}
}
// for(int i = 1; i <= n; i++, puts("")) for(int j = 1; j <= n; j++) printf("%d ", rn[i][j]);
// puts("");
// for(int i = 1; i <= n; i++, puts("")) for(int j = 1; j <= n; j++) printf("%d ", cn[i][j]);
// puts("");
fill(d + 1, d + C + cnt + 1, INF);
pq.push({0, rm + C});
pq.push({0, cm + C});
d[rm + C] = d[cm + C] = 0;
while(!pq.empty()){
pii c = pq.top();
pq.pop();
if(d[c.Y] < c.X) continue;
for(pii i : e[c.Y]){
if(c.X + i.Y < d[i.X]){
d[i.X] = c.X + i.Y;
pq.push({d[i.X], i.X});
}
}
}
//for(int i = 1; i <= cnt; i++) printf("%d : %d\n", i, d[i]);
for(pii i : e[rh + C]) if(i.Y) r = min(r, d[i.X + C] + i.Y);
for(pii i : e[ch + C]) if(i.Y) r = min(r, d[i.X + C] + i.Y);
printf("%d\n", r == INF ? -1 : r);
}
