// I stand with PALESTINE
//#pragma GCC optimize("Ofast,O3")
//#pragma GCC target("avx,avx2")
#include "bits/stdc++.h"
using namespace std;
using ll = long long;
template<typename T> struct SegTree {
vector<T> tree;
int size;
T neutral_element = 1e9; // sum - 0, mx - (-INF), mn - INF
inline T merge(T a, T b) {
return min(a, b);
}
void init(int n) {
size = 1;
while (size <= n) size *= 2;
tree.assign(2 * size, neutral_element);
}
void build(vector<T> &a) {
size = 1;
while (size < a.size()) size *= 2;
tree.assign(2 * size, neutral_element);
for (int i = size; i < size + a.size(); i++) tree[i] = a[i - size];
for (int i = size - 1; i > 0; i--) tree[i] = merge(tree[i << 1], tree[i << 1 | 1]);
}
void set(int p, T value) { // set value at position p
p += size;
tree[p] = merge(value, tree[p]);
for (; p > 1; p >>= 1) tree[p >> 1] = merge(tree[p], tree[p ^ 1]);
}
T get(int l, int r) { // sum on interval [l, r]
if (l > r) return neutral_element;
T res = neutral_element;
for (l += size, r += size + 1; l < r; l >>= 1, r >>= 1) {
if (l & 1) res = merge(res, tree[l++]);
if (r & 1) res = merge(res, tree[--r]);
}
return res;
}
};
void solve() {
int n;
string s, t;
cin >> n >> s >> t;
s = "&" + s; t = "&" + t;
auto find_ans = [&]() -> int {
SegTree<int> sg; sg.init(n + 1);
sg.set(0, 0);
int l1 = 0, l2 = 0, eq = 0;
for (int i = 1; i <= n; i++) {
// teng emas
if (s[i] != t[i]) l1++;
else l1 = 0;
if (l1) sg.set(i, sg.get(i - l1, i - 1) + 1);
// hammasi teng
if (s[i] == t[i]) eq++;
else eq = 0;
if (eq) sg.set(i, sg.get(i - eq, i - 1));
// bir hil qib qo'yish
if (t[i] == t[i - 1]) l2++;
else l2 = 1;
sg.set(i, sg.get(i - l2, i - 1) + 1);
// cout << i << ' ' << sg.get(i, i) << endl;
}
return sg.get(n, n);
};
int ans = find_ans();
for (int i = 1; i <= n; i++) s[i] ^= 1;
ans = min(ans, find_ans() + 1);
s = "&" + string(n, '0');
ans = min(ans, find_ans() + 1);
s = "&" + string(n, '1');
ans = min(ans, find_ans() + 1);
cout << ans;
}
int main() {
cin.tie(0)->sync_with_stdio(false);
#ifdef sunnatov
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
int q = 1;
// cin >> q;
while (q--) {
solve();
cout << '\n';
}
}
