#include <bits/stdc++.h>

using namespace std;

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

    string a, b;
    cin >> a >> b;

    int valasz = 1;
    for(int i = 1; i < n; i++){
        if((a[i - 1] == b[i - 1]) != (a[i] == b[i])){
            valasz++;
        }
    }

    if(a[n - 1] == b[n - 1]){
        valasz--;
    }

    cout << valasz << "\n";
}