func_code_string: #include <bits/stdc++.h>   using namespace std;   multiset<int> a, b;   int c[300010], d[300010];   int main() {     int n;     cin >> n;     for (int i = 1; i <= n; i++) {       cin >> c[i] >> d[i];       a.insert(c[i]);       b.insert(d[i]);     }     int ans = 0;     for (int i = 1; i <= n; i++) {       a.erase(a.find(c[i]));       b.erase(b.find(d[i]));       ans = max(ans, *b.begin() - *a.rbegin());       a.insert(c[i]);       b.insert(d[i]);     }     cout << ans << endl;   }   