#include "bits/stdc++.h"
using namespace std;
#define all(x) begin(x),end(x)
template<typename A, typename B> ostream& operator<<(ostream &os, const pair<A, B> &p) { return os << '(' << p.first << ", " << p.second << ')'; }
template<typename T_container, typename T = typename enable_if<!is_same<T_container, string>::value, typename T_container::value_type>::type> ostream& operator<<(ostream &os, const T_container &v) { string sep; for (const T &x : v) os << sep << x, sep = " "; return os; }
#define debug(a) cerr << "(" << #a << ": " << a << ")\n";
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> pi;
const int mxN = 1e5+1, oo = 1e9;
int main() {
int n; cin >> n;
string a,b; cin >> a >> b;
for(auto& i : a) i-='0';
for(auto& i : b) i-='0';
for(int i=n-1;i>0;--i) {
a[i] ^= a[i-1];
b[i] ^= b[i-1];
}
ll dp=0,dp2=oo;
for(int i=0;i<n;++i) {
tie(dp,dp2) = make_pair(min(dp+(a[i]!=b[i]), dp2+1), min(dp+2,dp2+b[i]));
}
cout << (min(dp,dp2)+1)/2;
}
