#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n;
  cin >> n;
  char str1[n + 1], str2[n + 1];
  long long int i, j, t;
  for (i = 0; i < n; i++) cin >> str1[i];
  for (i = 0; i < n; i++) cin >> str2[i];
  long long int val = 0;
  int arr[n];
  for (i = 0; i < n; i++) arr[i] = 0;
  for (i = 0; i < n; i++) {
    if (str1[i] == str2[i])
      continue;
    else if (str1[i] != str2[i] && arr[i] == 0) {
      if (str1[i] == str1[n - 1 - i] && str2[i] == str2[n - 1 - i]) {
        if (n % 2 != 0 && i == (n - 1) / 2) {
          val += 1;
        } else
          continue;
      } else if (str1[i] == str2[n - 1 - i]) {
        if (str2[i] == str1[n - 1 - i])
          continue;
        else {
          char temp = str2[n - 1 - i];
          str2[n - 1 - i] = str2[i];
          str2[i] = temp;
          arr[n - 1 - i] = 1;
          val += 1;
        }
      } else if (str2[i] == str1[n - 1 - i]) {
        if (str1[i] == str2[n - 1 - i])
          continue;
        else {
          char temp = str1[n - 1 - i];
          str1[n - 1 - i] = str1[i];
          str1[i] = temp;
          arr[n - 1 - i] = 1;
          val += 1;
        }
      } else if ((str2[i] == str2[n - 1 - i] && str1[i] != str1[n - 1 - i])) {
        arr[n - 1 - i] = 1;
        val += 1;
      } else {
        val += 1;
      }
    }
  }
  cout << val;
}
