#include <bits/stdc++.h>
constexpr int N = 1000000;
int dp[N + 1][2][2][2];
int main() {
std::ios::sync_with_stdio(false);
std::cin.tie(nullptr);
int n;
std::cin >> n;
std::string a, b;
std::cin >> a >> b;
a = "#" + a;
b = "#" + b;
// [pos][0][1][xor]
memset(dp, 0x3f, sizeof dp);
dp[0][0][0][0] = 0;
for (int i = 1; i <= n; i++) {
for (int a0 = 0; a0 < 2; a0++)
for (int a1 = 0; a1 < 2; a1++)
for (int xr = 0; xr < 2; xr++) {
char t = a[i];
if (a0) t = '0';
if (a1) t = '1';
if (xr) t ^= 1;
if (t != b[i]) {
continue;
}
int &ret = dp[i][a0][a1][xr];
ret = dp[i - 1][a0][a1][xr] - a0 - a1 - xr;
ret = std::min(ret, dp[i - 1][0][a1][xr] - a1 - xr);
ret = std::min(ret, dp[i - 1][a0][0][xr] - a0 - xr);
ret = std::min(ret, dp[i - 1][0][0][xr] - xr);
ret = std::min(ret, dp[i - 1][0][a1][0] - a1);
ret = std::min(ret, dp[i - 1][a0][0][0] - a0);
ret = std::min(ret, dp[i - 1][0][0][0]);
ret = std::min(ret, dp[i - 1][1][a1][xr] - (a0 == 1) - a1 - xr);
ret = std::min(ret, dp[i - 1][a0][1][xr] - a0 - (a1 == 1) - xr);
ret = std::min(ret, dp[i - 1][1][1][xr] - (a0 == 1) - (a1 == 1) - xr);
ret = std::min(ret, dp[i - 1][1][a1][1] - (a0 == 1) - a1 - (xr == 1));
ret = std::min(ret, dp[i - 1][a0][1][1] - a0 - (a1 == 1) - (xr == 1));
ret = std::min(ret, dp[i - 1][1][1][1] - (a0 == 1) - (a1 == 1) - (xr == 1));
ret += a0 + a1 + xr;
}
}
int ans = n;
for (int a0 = 0; a0 < 2; a0++)
for (int a1 = 0; a1 < 2; a1++)
for (int xr = 0; xr < 2; xr++)
ans = std::min(ans, dp[n][a0][a1][xr]);
std::cout << ans << "\n";
return 0;
}
