#include <bits/stdc++.h>
using namespace std;
long long inline gcd(long long x, long long y) {
  return !y ? (long long)abs(x) : gcd(y, x % y);
}
long long inline lcm(long long a, long long b) {
  return ((long long)abs((a / gcd(a, b)) * b));
}
double inline cartesian_dist(double x1, double y1, double x2, double y2) {
  return sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));
}
long long bigmod(long long b, long long p, long long m) {
  if (!p)
    return 1 % m;
  else if (p & 1)
    return (((b % m) + m) % m * bigmod(b, p - 1, m)) % m;
  else {
    long long ret = bigmod(b, p / 2, m);
    return (ret * ret) % m;
  }
}
long long inverse(long long a, long long m) { return bigmod(a, m - 2, m); }
long long extended(long long a, long long m) {
  long long oldr = a, r = m, oldans = 1, ans = 0, quotient;
  while (r) {
    quotient = oldr / r;
    oldr = oldr - r * quotient;
    swap(oldr, r);
    oldans = oldans - ans * quotient;
    swap(oldans, ans);
  }
  return ((oldans % m) + m) % m;
}
const double PI = acos(-1.0);
const double EPS = 10E-7;
int main() {
  int n;
  string s;
  while (1 == scanf("%d", &n)) {
    vector<string> vec;
    for (int i = 0; i < n; i++) {
      cin >> s;
      s += s;
      vec.push_back(s);
    }
    int len = (vec[0].size()) / 2;
    int ans = INT_MAX;
    for (int i = 0; i < len; i++) {
      string temp = vec[0].substr(i, len);
      int now = 0;
      for (int j = 0; j < vec.size(); j++) {
        bool found = false;
        for (int k = 0; k < len && !found; k++) {
          if (vec[j].substr(k, len) == temp) {
            found = true;
            now += k;
          }
        }
        if (!found) {
          cout << "-1" << endl;
          return 0;
        }
      }
      ans = min(ans, now);
    }
    cout << ans << endl;
  }
  return 0;
}
