#pragma GCC optimize("Ofast")
#pragma GCC optimize("no-stack-protector")
//#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("fast-math")
#pragma GCC target("sse,sse2,sse3,ssse3,popcnt,abm,mmx,tune=native")
#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <stdio.h>
#include <cstdio>
#include <math.h>
#include <cmath>
#include <string>
#include <cstring>
#include <queue>
#include <deque>
#include <random>
#include <iomanip>
#include <bitset>
using namespace std;
template<typename T> void uin(T &a, T b) {
if (b < a) {
a = b;
}
}
template<typename T> void uax(T &a, T b) {
if (b > a) {
a = b;
}
}
#define ghost signed
#define left left228
#define right right228
#define complex complex228
#define count count228
#define sin sin228
#define list list228
const int N = 1000 * 1000 + 228;
const int INF = 1e9 + 228;
int n;
int s[N], t[N];
int dp[N][3][2];
int color[N][3];
/*
0 - none
1 - color 0
2 - color 1
*/
ghost main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cin >> n;
char chaaa;
for (int i = 1; i <= n; ++i) {
cin >> chaaa;
s[i] = (chaaa - '0');
}
for (int i = 1; i <= n; ++i) {
cin >> chaaa;
t[i] = (chaaa - '0');
}
for (int i = 1; i <= n; ++i) {
color[i][0] = s[i];
color[i][1] = 0;
color[i][2] = 1;
}
for (int i = 1; i <= n; ++i) {
for (int c1 = 0; c1 < 3; ++c1) {
for (int c2 = 0; c2 < 2; ++c2) {
dp[i][c1][c2] = INF;
}
}
}
for (int c1 = 0; c1 < 3; ++c1) {
for (int c2 = 0; c2 < 1; ++c2) {
if ((color[1][c1] ^ c2) == t[1]) {
dp[1][c1][c2] = (c1 > 0) + (c2 > 0);
}
}
}
for (int i = 1; i < n; ++i) {
for (int c1 = 0; c1 < 3; ++c1) {
for (int c2 = 0; c2 < 2; ++c2) {
if (dp[i][c1][c2] == INF) continue;
for (int b1 = 0; b1 < 3; ++b1) {
for (int b2 = 0; b2 < 2; ++b2) {
if ((color[i + 1][b1] ^ b2) != t[i + 1]) continue;
uin(dp[i + 1][b1][b2], dp[i][c1][c2] + (b1 && b1 != c1) + (b2 && b2 != c2));
}
}
}
}
}
int res = INF;
for (int c1 = 0; c1 < 3; ++c1) {
for (int c2 = 0; c2 < 2; ++c2) uin(res, dp[n][c1][c2]);
}
cout << res << '\n';
return 0;
} // kek ;
// Ого! Кажетсья это $#@!
