func_code_string: #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;   }   