func_code_string: #include <bits/stdc++.h>   using namespace std;   int gcd(int a, int b) {     if (a == 0) return b;     return gcd(b % a, a);   }   long long int power(long long int x, long long int y, long long int p) {     long long int res = 1;     x = x % p;     while (y > 0) {       if (y & 1) res = (res * x) % p;       y = y >> 1;       x = (x * x) % p;     }     return res;   }   int main() {     int n;     cin >> n;     long long int n1 = 0, n0 = 0, x1 = 0, x0 = 0;     string a, b;     cin >> a >> b;     for (int i = 0; i < n; i++) {       if (a[i] ==  0  && b[i] ==  1 ) n0++;       if (a[i] ==  1  && b[i] ==  1 ) n1++;       if (a[i] ==  1  && b[i] ==  0 ) x1++;       if (a[i] ==  0  && b[i] ==  0 ) x0++;     }     long long int ans = 0;     for (int i = 0; i < n; i++) {       if (b[i] ==  0 ) {         if (a[i] ==  1 )           ans += n0;         else           ans += n1;       }     }     ans += x1 * x0;     cout << ans;     return 0;   }   