#include <bits/stdc++.h>
using namespace std;
#define short int32_t
#define int int64_t
#define long __int128_t
const int inf{numeric_limits<int>::max() / 4};
short main() {
#ifndef LOCAL
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
#endif
int n;
string a, b;
cin >> n >> a >> b;
a = "0" + a;
b = "0" + b;
vector<array<int, 3>> dp(n + 1);
for (int i{0}; i <= n; i++) {
for (int j{0}; j < 3; j++) {
dp[i][j] = inf;
}
}
dp[0][2] = 0;
for (int i{1}; i <= n; i++) {
for (int j{0}; j < 3; j++) {
for (int j2{0}; j2 < 3; j2++) {
int prev_char{j2 == 2 ? a[i - 1] - '0' : j2};
bool prev_correct{prev_char == b[i - 1] - '0'};
int curr_char{j == 2 ? a[i] - '0' : j};
bool curr_correct{curr_char == b[i] - '0'};
dp[i][j] = min(
dp[i][j],
dp[i - 1][j2] + (j != j2 && j != 2) + (prev_correct && !curr_correct)
);
}
}
}
cout << min({dp[n][0], dp[n][1], dp[n][2]}) << "\n";
return 0;
}
