#include<bits/stdc++.h>
using namespace std;
#define maxn 200002

int n, odp;
string a, b;

int main(){
	cin>>n;
	cin>>a>>b;
	a='#'+a;
	b='#'+b;
	for(int i=1; i<=n; i++){
		if(a[i]!=b[i]){
			bool ok=0;
			if(i<=(n/2)){
				if(a[n-i+1]==b[i]){
					a[n-i+1]=a[i];
					ok=1;
				}
				else if(b[n-i+1]==b[i]){
					b[n-i+1]=a[i];
					ok=1;
				}
				if(ok==0){
					if(a[n-i+1]==a[i] && b[n-i+1]==b[i]){
						a[n-i+1]=b[i];
						ok=1;
					}
					else if(b[n-i+1]==a[i]){
						b[n-i+1]=b[i];
						ok=1;
					}
				}
			}
			if(ok==0) odp++;
		}
	}
	cout<<odp;
}