#include<bits/stdc++.h>
#include<atcoder/all>
#include<string>
#include<vector>
#include<algorithm>
#include<map>
#include<math.h>
#include<set>
#include<regex>
#include<deque>
#include<queue>
#define all(x) x.begin(),x.end()
#define gall(x) x.begin(),x.end(),greater<>()
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define pb push_back
#define ll long long 
#define P pair<int,int>
#define LP pair<ll,ll>
using namespace std;
using namespace atcoder;


int main(){
int n; cin>>n;
string s,t; cin>>s>>t;
int ans=0;
bool f=0;
rep(i,n){
   if(!f){
   if(s[i]!=t[n-1-i]){
      ans++;
   } 
   }
   else {
      if(s[i]!=t[i]) ans++;
   }
}
cout<<ans<<endl;





return 0;
}