/// I'm only brave when I have to be
#include <bits/stdc++.h>
#define F first
#define S second
#define pb push_back
#define ppb pop_back
#define fast_io ios::sync_with_stdio(false);cin.tie(NULL);
#define file_io freopen("input.txt","r",stdin);freopen("output.txt","w",stdout);
#define FOR(i,k,n) for(int i = k; i < n; ++ i)
#define debf cout<<"(0-0)\n";
#define all(x) x.begin(), x.end()
#define dec(x) cout << fixed << setprecision(x);
#define pf push_front
#define ppf pop_front
#define dash " ------- "
#define what(x) cerr << #x << " is " << x << endl;
#define eb emplace_back
//#define int short int
#define int long long
#define sz(s) (int) (s.size())
#define fl cout.flush()
using namespace std;
typedef long long ll;
typedef pair <int, int> pii;
typedef pair <int, pii> pip;
typedef pair <pii, int> ppi;
typedef pair <ll, ll> pll;
typedef unsigned long long ull;
typedef long double ld;
template <class T> using max_heap = priority_queue <T, vector <T>, less <T> >;
template <class T> using min_heap = priority_queue <T, vector <T>, greater <T> >;
constexpr int MOD = 1e9 + 7, N = 1e6 + 8, M = 1e9, SQ = 500, INF = 1e9 + 8, LGN = 22, mod = 998244353, P = 131113;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int n, dp[N][3][2];
string s, t;
int32_t main(){
fast_io;
cin >> n >> s >> t;
for (int i = 0; i <= n; ++ i){
for (int j = 0; j < 3; ++ j){
dp[i][j][0] = INF;
dp[i][j][1] = INF;
}
}
dp[0][2][0] = 0;
for (int i = 0; i <= n; ++ i){
for (int j = 0; j < 3; ++ j){
for (int k = 0; k < 2; ++ k){
int cur = 0;
if (j == 2){
cur = ((s[i-1] - '0') ^ k);
}
else {
cur = (j ^ k);
}
if (cur == t[i-1] - '0'){
for (int jj = 0; jj < 3; ++ jj){
for (int kk = 0; kk < 2; ++ kk){
int xx = 0;
if (jj != j && j != 2){
++ xx;
}
if (k != kk && k == 1){
++ xx;
}
dp[i][j][k] = min (dp[i][j][k], dp[i-1][jj][kk] + xx);
}
}
}
}
}
}
cout << min (dp[n][0][0], min (dp[n][0][1], min (dp[n][1][0], min (dp[n][1][1], min (dp[n][2][0], dp[n][2][0])))));
return 0;
}
// Yesterday is history
// Tomorrow is a mystery
// but today is a gift
// That is why it is called the present
