#include "bits/stdc++.h"
#define int long long
using namespace std;
mt19937_64 rng((int) std::chrono::steady_clock::now().time_since_epoch().count());
int rnd(int x, int y) {
return uniform_int_distribution<int>(x, y)(rng);
}
const int MAXN = 1e6 + 10;
string a, b;
int n;
int ps[MAXN];
int dpf(int l, int r, int tog) {
while(l <= r && (a[l] ^ tog) == b[l]) l++;
while(l <= r && (a[r] ^ tog) == b[r]) r--;
if(l > r) return 0;
int nums = ps[r] - ps[l];
int cnt0, cnt1;
if(nums % 2 == 1) {
cnt0 = cnt1 = (nums + 1) / 2;
}
else {
cnt0 = nums / 2 + 1, cnt1 = nums / 2;
if(b[l] == '1') swap(cnt0, cnt1);
}
//cout << l << " " << r << " " << cnt0 << " " << cnt1 << "\n";
// set, then bruhopen
int ans = 1 + min(cnt0, cnt1);
ans = min(ans, 1 + dpf(l, r, tog ^ 1));
return ans;
}
void solve(int tc) {
cin >> n;
cin >> a >> b;
a = " " + a;
b = " " + b;
for(int i=2; i<=n; i++) ps[i] = ps[i-1] + (b[i] != b[i-1]);
cout << dpf(1, n, 0) << '\n';
}
int32_t main() {
ios::sync_with_stdio(0);
cin.tie(0);
int t = 1;
// cin >> t;
for(int i=1; i<=t; i++) solve(i);
}
/*
g++ T2421.cpp -std=c++17 -O2 -o T2421
./T2421 < input.txt
*/
