#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;
vi dp(n + 1), sMn(3, 0), id(3, 0);
FOR(i, 1, n){
id[0] += B[i - 1] != '0' && B[i] == '0';
id[1] += B[i - 1] != '1' && B[i] == '1';
id[2] += B[i - 1] == A[i - 1] && B[i] != A[i];
dp[i] = 1e9;
FOR(j, 0, 2){
ckmn(dp[i], id[j] + sMn[j] + (j < 2));
}
if(i < n){
ckmn(sMn[0], dp[i] - (id[0] - (B[i] == '0' && B[i + 1] == '0')));
ckmn(sMn[1], dp[i] - (id[1] - (B[i] == '1' && B[i + 1] == '1')));
ckmn(sMn[2], dp[i] - (id[2] - (B[i] != A[i] && B[i + 1] != A[i + 1])));
}
}
cout << dp[n] << 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;
}
