#include <bits/stdc++.h>
using namespace std;
bool valid(vector<char> a) {
  sort(a.begin(), a.end());
  if (a[0] == a[1] and a[2] == a[3]) {
    return true;
  }
  return false;
}
long long score(vector<char> &a, vector<char> &b) {
  bool done[4] = {0, 0, 0, 0};
  long long match = 0;
  for (long long i = 0; i < a.size() / 2; i++) {
    for (long long j = 0; j < b.size() / 2; j++) {
      if (done[j]) continue;
      if (a[i] == b[j]) {
        done[j] = true;
        match++;
        break;
      }
    }
  }
  return 2 - match;
}
long long solve(vector<char> a) {
  if (a.size() == 2) {
    if (a[0] == a[1]) return 0;
    return 1;
  }
  long long res = 1e9;
  vector<char> temp;
  temp.push_back(a[2]);
  temp.push_back(a[3]);
  temp.push_back(a[2]);
  temp.push_back(a[3]);
  long long cur = score(a, temp);
  res = min(res, cur);
  temp.clear();
  temp.push_back(a[0]);
  temp.push_back(a[0]);
  temp.push_back(a[2]);
  temp.push_back(a[3]);
  if (valid(temp)) cur = score(a, temp);
  res = min(res, cur);
  temp.clear();
  temp.push_back(a[1]);
  temp.push_back(a[1]);
  temp.push_back(a[2]);
  temp.push_back(a[3]);
  if (valid(temp)) cur = score(a, temp);
  res = min(res, cur);
  sort(a.begin(), a.end());
  if (valid(a)) return 0;
  return res;
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  long long n;
  cin >> n;
  string a;
  cin >> a;
  string b;
  cin >> b;
  vector<vector<char>> v;
  long long i = 0;
  long long j = n - 1;
  while (i <= j) {
    if (i == j) {
      vector<char> temp;
      temp.push_back(a[j]);
      temp.push_back(b[j]);
      v.push_back(temp);
      break;
    } else {
      vector<char> temp;
      temp.push_back(a[i]);
      temp.push_back(a[j]);
      temp.push_back(b[i]);
      temp.push_back(b[j]);
      v.push_back(temp);
      i++;
      j--;
    }
  }
  long long res = 0;
  for (long long i = 0; i < v.size(); i++) {
    res += (solve(v[i]));
  }
  cout << res << '\n';
  return 0;
}
