#include <bits/stdc++.h>
#define int long long
using namespace std;
const int INF = 1e9;
const int MX = (int)1e6 + 42;
int dp[MX][3][2];
void solve(int tcId) {
int n;
cin >> n;
vector<int> a (n + 1, 0);
vector<int> b (n + 1, 0);
for (int i = 1; i <= n; i++) {
char v;
cin >> v;
a[i] = v - '0';
}
for (int i = 1; i <= n; i++) {
char v;
cin >> v;
b[i] = v - '0';
}
for (int i = 0; i <= n; i++)
for (int j = 0; j < 3; j++)
for (int k = 0; k < 2; k++)
dp[i][j][k] = INF;
dp[0][2][0] = 0;
for (int i = 1; i <= n; i++) {
for (int j = 0; j < 3; j++) {
for (int k = 0; k < 2; k++) {
for (int pJ = 0; pJ < 3; pJ++) {
for (int pk = 0; pk < 2; pk++) {
int cnt = 0;
if (pJ != j && j != 2)
cnt++;
if (k != pk && k != 0)
cnt++;
int v = a[i];
if (j == 0) v = 0;
else if (j == 1) v = 1;
if (k) v ^= 1;
if (v == b[i])
dp[i][j][k] = min(dp[i][j][k], dp[i - 1][pJ][pk] + cnt);
}
}
}
}
}
int ans = 1e18;
for (int i = 0; i < 3; i++)
for (int j = 0; j < 2; j++)
ans = min(ans, dp[n][i][j]);
cout << ans << '\n';
}
signed main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
solve(42);
}
