#include <bits/stdc++.h>
using namespace std;
mt19937 RNG(chrono::steady_clock::now().time_since_epoch().count());
template <typename T>
T ceil(T a, T b) {
  return (a + b - 1) / b;
}
template <typename T>
T binpow(T a, T b) {
  T res = 1;
  while (b > 0) {
    if (b & 1) res = res * a;
    a = a * a;
    b >>= 1;
  }
  return res;
}
void solve() {
  long long n, c = 0;
  string s, t;
  cin >> n;
  cin >> s >> t;
  if (n == 1) {
    if (s == t) {
      cout << 0;
    } else {
      cout << 1;
    }
    return;
  }
  vector<long long> a, b;
  for (long long i = 1; i < n; i++) {
    if (s[i] != t[i] && s[i - 1] != t[i - 1]) {
      pair<char, char> a, b;
      a = {s[i], t[i]};
      b = {s[i - 1], t[i - 1]};
      if (a != b) {
        swap(s[i - 1], s[i]);
        c++;
      }
    }
  }
  for (long long i = 0; i < n; i++) {
    c += (s[i] != t[i]);
  }
  cout << c << "\n";
}
signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  long long t = 1;
  for (long long i = 1; i < t + 1; i++) {
    solve();
  }
  cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
  return 0;
}
