#include <bits/stdc++.h>
using namespace std;
int N, a[100005], b[100005];
char s1[100005], s2[100005];
long long x11, x01, x10, x00, ans;
int main() {
  scanf("%d", &N);
  cin >> s1;
  cin >> s2;
  for (int i = 1; i <= N; ++i) a[i] = s1[i - 1] - '0', b[i] = s2[i - 1] - '0';
  for (int i = 1; i <= N; ++i) {
    if (!a[i] && !b[i])
      x00++;
    else if (!a[i] && b[i])
      x01++;
    else if (a[i] && !b[i])
      x10++;
    else
      x11++;
  }
  ans = x11 * x00 + x00 * x10 + x10 * x01;
  cout << ans << endl;
  return 0;
}
