func_code_string: #include <bits/stdc++.h>   using namespace std;   class TaskD {    public:     void solve(std::istream &in, std::ostream &out) {       long long n;       in >> n;       vector<long long> a(n), b(n), sa(n), sb(n);       for (auto &i : a) in >> i;       for (auto &i : b) in >> i;       for (long long i = 0; i < n; ++i) {         sa[i] = a[i] - b[i];         sb[i] = b[i] - a[i];       }       sort((sa).begin(), (sa).end());       sort((sb).begin(), (sb).end());       long long ans = 0;       for (long long i = 0; i < n; ++i) {         ans += (long long)(sa.end() -                            lower_bound((sa).begin(), (sa).end(), sb[i] + 1));         if (sb[i] < 0) ans -= 1;       }       out << ans / 2 << endl;     }   };   signed main() {     TaskD solver;     std::istream &in(std::cin);     std::ostream &out(std::cout);     solver.solve(in, out);     return 0;   }   