#include "bits/stdc++.h"

using namespace std;

int main(){
    int n;cin>>n;
    string a,b;
    cin>>a>>b;

    int diff[n];
    for(int i=0;i<n;i++){
        if(a[i]==b[i]) diff[i]=0;
        else diff[i]=1;
    }

    int cnt=0;
    for(int i=0;i<n;i++){
        if(diff[i]==1){
            if(i==0 || diff[i-1]==0){
                cnt++;
            }
        }
    }
    cout<<cnt<<endl;
}