#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
#define pb push_back
#define pii pair<int, int>
#define pll pair<ll, ll>
#define st first
#define nd second
#define ordered_set tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>
#define debug false
const int MAXN = 1000 * 1000 + 17;
string a, b, b2;
int dp[MAXN][3][2];
int main () {
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int n;
cin >> n >> a >> b;
a = "#" + a;
b = "#" + b;
for (int i = 0; i <= n; i ++) {
for (int j = 0; j < 3; j ++) {
for (int k = 0; k < 2; k ++) {
dp[i][j][k] = MAXN;
}
}
}
dp[0][0][0] = 0;
for (int i = 1; i <= n; i ++) {
for (int j = 0; j < 3; j ++) {
for (int k = 0; k < 2; k ++) {
int x = int(a[i]) - int('0');
if (j == 1) {
x = 0;
}
if (j == 2) {
x = 1;
}
if (k == 1) {
x ^= 1;
}
if (x == (int(b[i]) - int('0'))) {
for (int j2 = 0; j2 < 3; j2 ++) {
for (int k2 = 0; k2 < 2; k2 ++) {
int c = 0;
if (j != 0 && j2 != j) {
c ++;
}
if (k != 0 && k2 != k) {
c ++;
}
dp[i][j][k] = min(dp[i][j][k], dp[i - 1][j2][k2] + c);
}
}
}
}
}
}
int w = MAXN;
for (int i = 0; i < 3; i ++) {
for (int j = 0; j < 2; j ++) {
w = min(w, dp[n][i][j]);
}
}
cout << w << "\n";
return 0;
}
