#include <bits/stdc++.h>   using namespace std;   const int maxn = 102400;   long long n, ans, c00, c01, c10, c11;   string a, b;   int main() {     cin >> n >> a >> b;     for (int i = 0; i < n; i++) {       if (a[i] ==  0  && b[i] ==  0 )         c00++;       else if (a[i] ==  0  && b[i] ==  1 )         c01++;       else if (a[i] ==  1  && b[i] ==  0 )         c10++;       else if (a[i] ==  1  && b[i] ==  1 )         c11++;     }     for (int i = 0; i < n; i++) {       if (a[i] ==  0  && b[i] ==  0 )         ans += (c10 + c11);       else if (a[i] ==  0  && b[i] ==  1 )         ans += c10;       else if (a[i] ==  1  && b[i] ==  0 )         ans += (c00 + c01);       else if (a[i] ==  1  && b[i] ==  1 )         ans += c00;     }     cout << ans / 2 << endl;   }   