//#pragma GCC target("avx2")
//#pragma GCC optimize("O3")
//# include <x86intrin.h>
# include <bits/stdc++.h>
# include <ext/pb_ds/assoc_container.hpp>
# include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
template<typename T> using ordered_set = tree <T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#define _USE_MATH_DEFINES_
#define ll long long
#define ld long double
#define Accepted 0
#define pb push_back
#define mp make_pair
#define sz(x) (int)(x.size())
#define every(x) x.begin(),x.end()
#define F first
#define S second
#define lb lower_bound
#define ub upper_bound
#define For(i,x,y) for (ll i = x; i <= y; i ++)
#define FOr(i,x,y) for (ll i = x; i >= y; i --)
#define SpeedForce ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0)
// ROAD to... Red
inline void Input_Output () {
//freopen(".in", "r", stdin);
//freopen(".out", "w", stdout);
}
const double eps = 0.000001;
const ld pi = acos(-1);
const int maxn = 1e7 + 9;
const int mod = 1e9 + 7;
const ll MOD = 1e18 + 9;
const ll INF = 1e18 + 123;
const int inf = 2e9 + 11;
const int mxn = 1e6 + 9;
const int N = 6e5 + 123;
const int M = 22;
const int pri = 997;
const int Magic = 2101;
const int dx[] = {-1, 0, 1, 0};
const int dy[] = {0, -1, 0, 1};
int n;
string s, t;
int dp[33];
void upd (int &a, int b) {
if (a > b) a = b;
}
char op (int j, char c) {
if (2 <= j && j <= 3) c = '0';
if (4 <= j && j <= 7) c = '1';
if (8 <= j && j <= 9) c = '0';
if (j & 1) c = char('0'+(1-(c-'0')));
return c;
}
void process () {
for (int i = 1; i < 10; i += 2) upd(dp[i-1], dp[i]); // remove toggle
for (int i = 8; i <= 9; i ++) upd(dp[i-4], dp[i]); // remove white
for (int i = 6; i <= 7; i ++) upd(dp[i-4], dp[i]); // remove black
for (int i = 4; i <= 5; i ++) upd(dp[i-4], dp[i]); // remove black
for (int i = 2; i <= 3; i ++) upd(dp[i-2], dp[i]); // remove white
for (int i = 2; i <= 3; i ++) upd(dp[i], dp[i-2]+1); // add white
for (int i = 4; i <= 5; i ++) upd(dp[i], dp[i-4]+1); // add black
for (int i = 6; i <= 7; i ++) upd(dp[i], dp[i-4]+1); // add black
for (int i = 8; i <= 9; i ++) upd(dp[i], dp[i-4]+1); // add white
for (int i = 1; i < 10; i += 2) upd(dp[i], dp[i-1]+1); //toggle add
}
int main () {
SpeedForce;
cin >> n;
cin >> s >> t;
for (int j = 1; j <= 10; ++j) dp[j] = inf;
for (int i = 0; i < n; i ++) {
process();
for (int j = 0; j < 11; ++j)
if (op(j, s[i]) != t[i])
dp[j] = inf;
}
cout << *min_element(dp, dp + 11) << '\n';
return Accepted;
}
// B...a
