/* in the name of allah */
#include<bits/stdc++.h>
using namespace std;
#define endl '\n'
#define pb push_back
#define F first
#define S second
#define mk make_pair
typedef long long ll;
const int N=1e6+7;
int n,nxt[N],bad[N],s[N];
string a,b,c;
int solve(string a,string b){
int ans=0;
nxt[n-1]=n-1;
for(int i=n-2;i>=0;i--){
nxt[i]=i;
if(b[i]==b[i+1])nxt[i]=nxt[i+1];
}
for(int i=0;i<n;i++){
if(a[i]!=b[i])s[i]=1;
else s[i]=0;
//cout<<s[i];
}
bad[n-1]=n-1;
for(int i=n-2;i>=0;i--){
bad[i]=i;
if(s[i]==s[i+1])bad[i]=bad[i+1];
}
for(int i=0;i<n;){
if(s[i]==0){
i++;
continue;
}
ans++;
i=max(bad[i]+1,nxt[i]+1);
}
//cout<<ans<<endl;
return ans;
}
int main(){
ios:: sync_with_stdio(0),cin.tie(0),cout.tie(0);
cin>>n;
cin>>a>>b;
int ans=solve(a,b);
for(int i=0;i<n;i++){
if(a[i]=='0')c+="1";
else c+="0";
}
ans=min(ans,1+solve(c,b));
cout<<ans<<endl;
}
