func_code_string: #include <bits/stdc++.h>   using namespace std;   long long a[200001], b[200001], c[200001];   int main() {     long long n, ans = 0;     cin >> n;     for (int i = 0; i < n; i++) cin >> a[i];     for (int i = 0; i < n; i++) cin >> b[i];     for (int i = 0; i < n; i++) c[i] = a[i] - b[i];     sort(c, c + n);     for (int i = n - 1;; i--) {       if (c[i] <= 0) break;       int ans1 = &c[i] - upper_bound(c, c + n, 0 - c[i]);       ans += ans1;     }     cout << ans << endl;     return 0;   }   