#include<bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
#define vi vector<int>
#define pi pair<int,int>
#define sz(v) (int)(v).size()
#define all(v) (v).begin(), (v).end()
#define compact(v) (v).erase(unique(all(v)), (v).end())
template<class T> using upq = priority_queue<T, vector<T>, greater<T>>;
template<class T> int lwrbound(const vector<T>& a, const T& b, const int s = 0){return int(lower_bound(s + all(a), b) - a.begin());}
template<class T> int uprbound(const vector<T>& a, const T& b, const int s = 0){return int(upper_bound(s + all(a), b) - a.begin());}
#define FOR(i, a, b) for(int i = (a); i <= (b); i++)
#define ROF(i, a, b) for(int i = (a); i >= (b); i--)
#define sumof(x) accumulate(all(x), 0ll)
#define dbg(x) "[" << #x " = " << (x) << "]"
#define el "\n"
using ll = long long;
using ld = long double;
template<class T> bool ckmx(T& a, const T b){return (a < b ? a = b, true : false);}
template<class T> bool ckmn(T& a, const T b){return (a > b ? a = b, true : false);}
void Main()
{
int n; cin >> n;
string A, B; cin >> A >> B;
A = " " + A;
B = " " + B;
vector<vi> dp(2, vi(3, 1e9));
dp[0][0] = 0;
FOR(i, 1, n){
vector<vi> ndp(2, vi(3, 1e9));
int t = (B[i] - '0');
FOR(b, 0, 1){
FOR(k, 0, 2){
int x = (k < 2 ? k : ((A[i] - '0') ^ b));
if(x == t){
FOR(b1, 0, 1){
FOR(k1, 0, 2){
ckmn(ndp[b][k], dp[b1][k1] + (b > b1) + (k < 2 && k != k1));
}
}
}
}
}
swap(ndp, dp);
}
int ans = 1e9;
FOR(b, 0, 1){
FOR(k, 0, 2) ckmn(ans, dp[b][k]);
}
cout << ans << el;
}
int32_t main()
{
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
#define name "InvMOD"
if(fopen(name".INP", "r")){
freopen(name".INP", "r", stdin);
freopen(name".OUT", "w", stdout);
}
int t = 1; while(t--) Main();
return 0;
}
