#include <bits/stdc++.h>
using namespace std;
const int N = 1'000'000 + 10;
int n;
int a[N], b[N];
const int MAX = 1'000'000'000;
int f[N][3];
int32_t main() {
cin.tie(0)->sync_with_stdio(0);
cin >> n;
for (int i = 1; i <= n; ++i) {
char ch; cin >> ch;
a[i] = (ch == '1');
}
for (int i = 1; i <= n; ++i) {
char ch; cin >> ch;
b[i] = (ch == '1');
}
auto useXor = [&](int i, int j) {
return !j ? a[i] != b[i] : (j - 1 != b[i]);
};
memset(f, 63, sizeof f);
f[1][0] = useXor(1, 0);
f[1][1] = 1 + useXor(1, 1);
f[1][2] = 1 + useXor(1, 2);
for (int i = 2; i <= n; ++i) {
{ // f[i][0] no assign line
auto& ret = f[i][0];
for (int j = 0; j <= 2; ++j) {
ret = min(ret, f[i - 1][j] + (useXor(i, 0) && !useXor(i - 1, j)));
}
}
{ // f[i][1] assign line is 0
auto& ret = f[i][1];
for (int j = 0; j <= 2; ++j) {
ret = min(ret, f[i - 1][j] + (j != 1) + (useXor(i, 1) && !useXor(i - 1, j)));
}
}
{ // f[i][1] assign line is 1
auto& ret = f[i][2];
for (int j = 0; j <= 2; ++j) {
ret = min(ret, f[i - 1][j] + (j != 2) + (useXor(i, 2) && !useXor(i - 1, j)));
}
}
}
cout << min({f[n][0], f[n][1], f[n][2]}) << "\n";
}
