#include <bits/stdc++.h>
using namespace std;
string str[51], temp;
int main() {
  int t, f, a;
  int cnt = 0, ans = 0x3f3f3f3f;
  scanf("%d", &t);
  getchar();
  for (int i = 0; i < t; i++) {
    cin >> str[i];
  }
  for (int i = 0; i < t; i++) {
    cnt = 0;
    for (int j = 0; j < t; j++) {
      temp = str[j] + str[j];
      if (temp.find(str[i]) == string::npos) {
        cout << -1 << endl;
        return 0;
      }
      cnt += temp.find(str[i]);
    }
    ans = min(ans, cnt);
  }
  cout << ans << endl;
  return 0;
}
