#include <bits/stdc++.h>
using namespace std;
#define finish(x) return cout << x << endl, 0
#define ll long long
const int N = 1000001;
int n, dp[N][2][2][2];
string a, b;
int calc(int idx, int is_off, int is_on, int is_toggle){
int ret = a[idx];
if(is_off) ret = 0;
if(is_on) ret = 1;
if(is_toggle) ret ^= 1;
return ret;
}
int solve(int idx, int is_off, int is_on, int is_toggle){
if(idx == n) return 0;
int &ret = dp[idx][is_off][is_on][is_toggle];
if(ret != -1) return ret;
ret = (int)1e9;
for(int x = 0 ; x < 2 ; x++){
for(int y = 0 ; y < 2 ; y++){
for(int z = 0 ; z < 2 ; z++){
if(x && y) continue;
if(calc(idx, x, y, z) == b[idx]){
ret = min(ret, solve(idx + 1, x, y, z) + max(0, x - is_off) + max(0, y - is_on) + max(0, z - is_toggle));
}
}
}
}
return ret;
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
memset(dp, -1, sizeof dp);
cin >> n >> a >> b;
for(auto &i : a) i -= '0';
for(auto &i : b) i -= '0';
cout << solve(0, 0, 0, 0) << endl;
}
