func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long MAX = 100005;   const long long mod = 1000000007;   const double PI = 2 * acos(0.0);   const double EPS = 0.00000000001;   int main() {     long long n;     cin >> n;     string a, b;     cin >> a >> b;     long long OO = 0, II = 0, IO = 0, OI = 0;     for (long long i = 0; i < n; i++) {       if (a[i] ==  1  and b[i] ==  1 )         II++;       else if (a[i] ==  0  and b[i] ==  0 )         OO++;       else if (a[i] ==  1  and b[i] ==  0 )         IO++;       else if (a[i] ==  0  and b[i] ==  1 )         OI++;     }     long long ans = (OO * II) + (OI * IO) + (OO * IO);     cout << ans << endl;     return 0;   }   