// iostream is too mainstream
#include <cstdio>
// bitch please
#include <iostream>
#include <vector>
#include <set>
#include <map>
#include <string>
#include <queue>
#include <stack>
#include <algorithm>
#include <iomanip>
#define dibs reserve
#define OVER9000 1234567890
#define patkan 9
#define tisic 47
#define soclose 10e-7
#define ALL_THE(CAKE,LIE) for(auto LIE =CAKE.begin(); LIE != CAKE.end(); LIE++)
#define chocolate win
#define ff first
#define ss second
#define abs(x) ((x < 0)?-(x):(x))
// mylittlepony
using namespace std;
	
	
int main() {
    cin.sync_with_stdio(0);
    int N;
    cin >> N;
    string s,t;
    cin >> s >> t;
    int ans =0, a =0;
    for(int i =0; i < N; i++) {
    	if(s[i] != t[i]) a++;
    	else if(a > 0) {
    		a =0;
    		ans++;}}
    if(a > 0) ans++;
    cout << ans << "\n";
    return 0;}
        
// look at my code
// my code is amazing