func_code_string: #include <bits/stdc++.h>   using namespace std;   int n;   vector<int> Left;   vector<int> Right;   map<pair<int, int>, int> excep;   int main() {     ios::sync_with_stdio(0);     cin.tie(0);     cout.tie();     cin >> n;     for (int i = 0; i < n; i++) {       int l, r;       cin >> l >> r;       Left.push_back(l);       Right.push_back(r);       excep[{l, r}] = 1;     }     sort(Left.begin(), Left.end(), greater<int>());     sort(Right.begin(), Right.end());     if (excep[{Left[0], Right[0]}] == 1)       cout << max(0, Right[1] - Left[1]);     else       cout << max(0, max(Right[0] - Left[1], Right[1] - Left[0]));   }   