#include <bits/stdc++.h>
using namespace std;

int main() {

    ios_base::sync_with_stdio(false);
    cin.tie(0);
    
    int n; cin >> n;
    string a, b; cin >> a >> b;
    int ugyan = -1, ans = 0;
    for (int i = 0; i < n; i++) {
        if (ugyan == -1) {
            if (a[i] == b[i]) ugyan = 0; // egyenlo
            else ugyan = 1; // kulonbozo
        } else if (ugyan == 0 && a[i] != b[i]) {
            cerr << i << ": " << i << " - " << "ugyanaz\n";
            ans++; ugyan = 1;
        } else if (ugyan == 1 && a[i] == b[i]) {
            cerr << i << ": " << i << " - " << "kulonbozik\n";
            ans++; ugyan = 0;
        }
    }
    if (ugyan == 1) ans++;
    cout << ans;
	
    return 0;
}