//#include"holiday.h"
#include <bits/stdc++.h>
#define ll long long
#define rep(i,m,n) for(int i=(m); i<=(n); i++)
#define reb(i,m,n) for(int i=(m); i>=(n); i--)
#define pii pair<int,int>
#define pll pair<ll,ll>
#define MP make_pair
#define fs first
#define se second
#define bit(msk, i) ((msk >> i) & 1)
#define iter(id, v) for(auto id : v)
#define pb push_back
#define SZ(v) (ll)v.size()
#define ALL(v) v.begin(),v.end()
using namespace std;
mt19937_64 rd(chrono :: steady_clock :: now ().time_since_epoch().count());
ll Rand (ll l, ll r) { return uniform_int_distribution<ll> (l, r) (rd); }
const int N = 1e6 + 7;
int Mod = 1e9 + 7;///lon
const int INF = 1e9;
const ll BASE = 137;
const int szBL = 450;
int n;
int a[N], b[N];
int dp[N][3][2];
void solution () {
cin >> n;
{
string s;
cin >> s;
rep (i, 1, n) a[i] = s[i - 1] - '0';
}
{
string s;
cin >> s;
rep (i, 1, n) b[i] = s[i - 1] - '0';
}
memset(dp, 0x3f, sizeof dp);
dp[0][2][0] = 0;
rep (i, 1, n) {
rep (j, 0, 2)
rep (k, 0, 1) {
int bt = j == 2 ? a[i] ^ k : j ^ k;
if (bt != b[i]) continue;
rep (j2, 0, 2)
rep (k2, 0, 1) {
dp[i][j][k] = min(dp[i][j][k], dp[i - 1][j2][k2] + (j2 != j && j != 2) + (k2 != k && k != 0));
}
}
}
int res = INF;
rep (j, 0, 2)
rep (k, 0, 1) res = min(res, dp[n][j][k]);
cout << res <<"\n";
}
#define file(name) freopen(name".inp","r",stdin); \
freopen(name".out","w",stdout);
int main () {
// file("c");
ios_base :: sync_with_stdio(false); cin.tie(0); cout.tie(0);
int num_Test = 1;
// cin >> num_Test;
while (num_Test--)
solution();
}
/*
no bug challenge +10
5 5
01101
10001
00110
10101
00100
*/
