Periods of Words

#include <bits/stdc++.h>
using namespace std;
using i64 = long long;
vector<int> getPi(const string &s) {
  int n = (int)s.size();
  vector<int> pi(n, 0);
  for (int i = 1, j = 0; i < n; ++i) {
    while (j > 0 and s[i] != s[j]) j = pi[j - 1];
    if (s[i] == s[j]) ++j;
    pi[i] = j;
  }
  return pi;
}
int main() {
  cin.tie(0)->sync_with_stdio(0);
  int n; cin >> n;
  string s; cin >> s;
  auto pi = getPi(s);
  i64 ans = 0;
  for (int i = n; i >= 2; --i) {
    int d = i - pi[i-1];
    if (i % d == 0) {
      ans += (i - d);
    } else {
      ans += (d * (i / d));
    }
  }
  cout << ans << '\n';
}
/*

b            ->          0
ba           ->          0
bab          -> ba       2
baba         -> ba       2
babab        -> baba     4
bababa       -> baba     4
bababab      -> bababa   6
babababa     -> bababa   6
total        =          24

*/