#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  string a, b;
  cin >> a >> b;
  a = "@" + a;
  b = "@" + b;
  int i = 1, j = n;
  int ans = 0;
  while (i <= j) {
    if (i == j && a[i] != b[i]) {
      ans++;
      break;
    }
    if (a[i] == b[i]) {
      if (a[j] == b[j]) {
      } else {
        ans++;
      }
    } else {
      if (a[j] == b[j]) {
        ans++;
      } else {
        if (a[j] == a[i]) {
          if (b[j] != b[i]) ans += 2;
        } else if (a[j] == b[i] && a[i] == b[j]) {
        } else if (a[j] == b[i]) {
          ans++;
        } else if (b[j] == a[i]) {
          ans++;
        } else if (b[i] == b[j])
          ans++;
        else {
          ans += 2;
        }
      }
    }
    i++;
    j--;
  }
  cout << ans;
}
