#include <bits/stdc++.h>
using namespace std;
const int N = 100 + 10;
bool vis1[N], vis2[N];
int main() {
  ios_base::sync_with_stdio(0);
  string a, b;
  int n;
  cin >> n >> a >> b;
  int sum = 0;
  for (int i = 0; i < n / 2; i++) {
    if (b[i] == b[n - i - 1]) {
      if (a[i] != a[n - i - 1]) sum++;
    } else
      sum += min((a[i] != b[i]) + (a[n - i - 1] != b[n - i - 1]),
                 (a[n - i - 1] != b[i]) + (b[n - i - 1] != a[i]));
  }
  if (n & 1) {
    if (a[n / 2] != b[n / 2]) sum++;
  }
  cout << sum << endl;
  return 0;
}
