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

int main() {
    int n;
    cin >> n;

    string s, t;
    cin >> s >> t;

    vector<bool> diff(n);
    for (int i = 0; i < n; i++) {
        diff[i] = (s[i] != t[i]);
    }

    int steps = 0;

    if (diff[0]) steps++;

    for (int i = 1; i < n; i++) {
        if (diff[i] != diff[i-1]) {
            steps++;
        }
    }

    cout << steps;
    return 0;
}