#include <bits/stdc++.h>
using namespace std;
string str[100];
int func(string s1, string s2) {
  int i, j, k;
  int l1 = s1.length(), l2 = s2.length();
  if (l1 != l2) return -1;
  for (i = 0; i < l1; ++i) {
    for (j = i, k = 0; k < l1; ++k, ++j) {
      j = j % l1;
      if (s1[k] != s2[j]) break;
    }
    if (k == l1) return i;
  }
  return -1;
}
int main() {
  int i, j, k;
  int n, cnt;
  cin >> n;
  for (i = 0; i < n; ++i) cin >> str[i];
  int mn = 1000000000;
  for (i = 0; i < n; ++i) {
    cnt = 0;
    for (j = 0; j < n; ++j) {
      if (i == j) continue;
      k = func(str[i], str[j]);
      if (k == -1) {
        printf("-1\n");
        return 0;
      }
      cnt += k;
    }
    mn = min(mn, cnt);
  }
  cout << mn << endl;
}
