import java.util.*;
import java.io.*;
import java.math.*;
import java.util.stream.Stream;

public class Main{

    static  PrintWriter output;
    static  Scanner sc;

    static void solve(){
        int n = ni();
        String s = ns();
        String t = ns();
        StringBuilder sb = new StringBuilder();
        sb.append(s);
        String r = sb.reverse().toString();
        int ans = 0;
        int same = 0;
        for(int i=0;i<n;i++) {
            if(s.charAt(i) != t.charAt(n-i-1)) ans++;
            if(r.charAt(i) == s.charAt(i)) same++;
        }
        output.print(same == n && !r.equals(t)? n : ans);
    }

    public static void main(String[] args) throws IOException{
        output = new PrintWriter(System.out);
        sc = new Scanner(System.in);
        solve();
        output.flush();
    }
    static int ni(){ return sc.nextInt();}
    static long nl(){ return sc.nextLong();}
    static String ns(){return sc.next();}
    static BigInteger bi(){return sc.nextBigInteger();}
    static BigDecimal bd(){return sc.nextBigDecimal();}
    static Map<Long,Integer> counter(long [] A) {
        HashMap<Long,Integer> count = new HashMap<>();
        for(int i=0;i<A.length;i++) {
            if(!count.containsKey(A[i])) count.put(A[i],1);
            else count.put(A[i],count.get(A[i])+1);
        }
        return count;
    }
}