#include <bits/stdc++.h>
const int MAXINT = 2147483640;
const long long MAXLL = 9223372036854775800LL;
const long long MAXN = 1e6;
const double eps = 1e-9;
const long long mod = 1e9 + 7;
using namespace std;
long long binpow(long long a, long long n) {
  long long ans = 1;
  while (n) {
    if (n & 1) ans *= a;
    a *= a;
    n >>= 1;
  }
  return ans;
}
long long n;
char a[MAXN], b[MAXN];
int main() {
  srand(time(0));
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  ;
  cin >> n;
  long long ans1 = 0, ans0 = 0;
  for (int i = 1; i <= n; ++i) {
    cin >> a[i];
    if (a[i] == '1')
      ans1++;
    else
      ans0++;
  }
  for (int i = 1; i <= n; ++i) {
    cin >> b[i];
  }
  long long ans = 0;
  for (int i = 1; i <= n; ++i) {
    if (a[i] == '0' && b[i] == '0') {
      ans += ans1;
      ans0--;
    }
    if (a[i] == '1' && b[i] == '0') {
      ans += ans0;
      ans1--;
    }
  }
  cout << ans << endl;
  return 0;
}
