#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ii = pair<int, int>;
using vi = vector<int>;
const int N = 1e6 + 6;
// msk = reset|set|toggle
int apply(int x, int msk) {
int ret = x;
if(msk & 4) ret = 0;
if(msk & 2) ret = 1;
if(msk & 1) ret ^= 1;
return ret;
}
int dp[N][1 << 3];
int n;
vi A, B;
int main(int argc, char const *argv[])
{
cin.sync_with_stdio(0); cin.tie(0);
cin.exceptions(cin.failbit);
#ifdef LOCAL
freopen("in", "r", stdin);
#endif
cin >> n;
#define read(v) { string s; cin >> s; \
for(int i = 0; i < n; i++) v.emplace_back(s[i] - '0'); }
read(A); read(B);
for(int u = 0; u < 8; u++) dp[n][u] = __builtin_popcount(u);
for(int i = n-1; i >= 0; i--) {
for(int u = 0; u < 8; u++) dp[i][u] = 1e9;
for(int u = 0; u < 8; u++) if((u & 6) != 6) {
for(int v = 0; v < 8; v++) if((v & 6) != 6) {
if(apply(A[i], v) == B[i]) {
dp[i][u] = min(dp[i][u], __builtin_popcount(u ^ v) + dp[i+1][v]);
}
}
}
}
cout << dp[0][0] / 2 << endl;
return 0;
}
