#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll=long long;
using ld=long double;
ll inf=10010010010010010;
ll mod=998244353;
int main(){
    ll n;
    cin >> n;
    string s,t;
    cin >> s >> t;
    ll x=0;
    for (ll i = 0; i < n; i++)
    {
        if (s[i]!=t[i])
        {
            x+=1;
        }
    }
    reverse(s.begin(),s.end());
    ll y=0;
    for (ll i = 0; i < n; i++)
    {
        if (s[i]!=t[i])
        {
            y+=1;
        }
    }
    cout << min(x,y) << endl;
}