// Success consists of going from failure to failure without loss of enthusiasm
#include <bits/stdc++.h>
using namespace std;
#define nl '\n'
#define pb push_back
#define pf push_front
#define mp make_pair
#define f first
#define s second
#define sz(x) int(x.size())
template<class T> using V = vector<T>;
using pi = pair<int, int>;
using vi = V<int>;
using vpi = V<pi>;
using ll = long long;
using pl = pair<ll, ll>;
using vpl = V<pl>;
using vl = V<ll>;
using db = long double;
using str = string;
template<class T> using pq = priority_queue<T, V<T>, greater<T>>;
const int MOD = 1e9 + 7;
const ll INFL = ll(1e17);
const int LG = 19;
int main() {
cin.tie(0)->sync_with_stdio(0);
int N; cin >> N;
str S; cin >> S;
str T; cin >> T;
V<vi> dp(N+1, vi(8, MOD)); // [flip][set 0][set 1]
dp[0][0] = 0;
for(int i = 0; i < N; i++) for(int x = 0; x < 8; x++) if (dp[i][x] != MOD) {
if (x & (x >> 1) & 1) continue;
// cout << i << " " << x << " " << dp[i][x] << endl;
for(int y = 0; y < 8; y++) {
if (y & (y >> 1) & 1) continue;
int cost = __builtin_popcount(x ^ y);
char c = S[i];
if ((y >> 0) & 1) c = '1';
if ((y >> 1) & 1) c = '0';
if ((y >> 2) & 1) c = '0' + '1' - c;
// cout << y << " " << c << endl;
if (c == T[i]) dp[i+1][y] = min(dp[i][x] + cost, dp[i+1][y]);
}
}
int ans = MOD;
for(int i = 0; i < 8; i++) ans = min(ans, dp.back()[i] + __builtin_popcount(i));
cout << ans / 2 << nl;
exit(0-0);
}
