#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e6 + 11;
int dp[maxn];
int n, ans;
string a, b;
bool yes(int i, int j) {
  bool ok = 1;
  ok &= a[i] != b[i];
  ok &= a[j] != b[j];
  ok &= a[i] != a[j];
  return ok;
}
void go() {
  for (int i = 0; i < n; i++) {
    ans++;
    if (i and yes(i - 1, i))
      swap(a[i - 1], a[i]);
    else if (i < n - 1 and yes(i, i + 1))
      swap(a[i], a[i + 1]);
    else
      ans--;
  }
}
int main() {
  ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  cin >> n >> a >> b;
  for (int i = 0; i < 10; i++) go();
  for (int i = 0; i < n; i++) ans += a[i] != b[i];
  cout << ans << endl;
}
