Language: C++

#include <bits/stdc++.h>
//#include <boost/multiprecision/cpp_int.hpp> 
//using boost::multiprecision::cpp_int;
using namespace std;
#define ll long long int
#define F first
#define S second
//#define endl "\n"
//#define nl cout<<endl;
#define pb push_back
#define ull unsigned long long 
#define f(i,a,b) for(ll i=a;i<b;i++)
#define Knucklehead ios_base::sync_with_stdio(false);cin.tie(NULL);
//#define mod 100000007
#define mat vector<vector<ll>>
mat cn(ll n, ll m){return vector< vector<ll> >(n, vector<ll>(m));}
bool compare(char &s1,char &s2){return s1 > s2;} 
bool sortmahstyle(const pair<ll,ll> &a,  const pair<ll,ll> &b) 
{ 
    if(a.second > b.second )
        return true;
    if( a.second==b.second && a.first > b.second )
       return true;
    return false;
}
bool cmp(int n, pair<int, int> const& p)
{
    return (p.first < n);
}
//me
ll const mod = 1e9+7;//998244353;
ll const inf = 1e18;
ll const maxn = 1e6+1;
ll f[maxn];
void factorial()
{
     f[0]=1;
     for(ll i = 1; i<maxn; i++)
          f[i] = (f[i-1]*i)%mod;
}

ll powmod(ll a, ll b)
{
     ll res = 1;
     while(b){
          if(b&1) res = (res*a)%mod;
          a = (a*a)%mod;
          b/=2;
     }
     return res;
}
ll inv(ll x)
{
     return powmod(x, mod-2);
}

ll choose(ll n, ll r)
{
     return ( (f[n]*inv(f[n-r]))%mod *inv(f[r])) % mod;
}
bool check(ll x1, ll y1, ll x2, ll y2)
{
     return (x1==x2 && y1==y2);
}

void solve()
{    
     
     ll n; cin >> n;
     array<ll,3> points[n];
     set<pair<<ll,ll> ss;
     f(i,0,n){
          cin >> points[i][1] >> points[i][2];
          ss.insert({points[i][1] , points[i][2]});
          points[i][0] = points[i][1] + points[i][2];
     }

     sort(points, points+n);
     ll ans = 0;
     for( auto e : ss){
        if( ss.count({e.S,e.F}))
        ans = max( ans, e.S+e.F );
     }
     cout << max(ans,abs(points[0][0]-points[n-1][0]));
     
}

int main() {
Knucklehead 
//*
#ifndef ONLINE_JUDGE
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
/**/ 
          //factorial();
          ll t;
          /**/t=1;
          /*/cin>>t;/**/
          f(testcases,0,t){
               //cout << "Case #" <<testcases+1<<": ";
               solve();
          }
 
 
    return 0;
}


Compiler output:
a.cc: In function 'void solve()':
a.cc:71:21: error: template argument 1 is invalid
   71 |      set<pair<<ll,ll> ss;
      |                     ^
a.cc:71:21: error: template argument 2 is invalid
a.cc:71:21: error: template argument 3 is invalid
a.cc:74:14: error: request for member 'insert' in 'ss', which is of non-class type 'int'
   74 |           ss.insert({points[i][1] , points[i][2]});
      |              ^~~~~~
a.cc:80:20: error: 'begin' was not declared in this scope
   80 |      for( auto e : ss){
      |                    ^~
a.cc:80:20: note: suggested alternatives:
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:166,
                 from a.cc:1:
/usr/include/c++/14/valarray:1238:5: note:   'std::begin'
 1238 |     begin(const valarray<_Tp>& __va) noexcept
      |     ^~~~~
In file included from /usr/include/c++/14/filesystem:53,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:200:
/usr/include/c++/14/bits/fs_dir.h:608:3: note:   'std::filesystem::__cxx11::begin'
  608 |   begin(recursive_directory_iterator __iter) noexcept
      |   ^~~~~
a.cc:80:20: error: 'end' was not declared in this scope
   80 |      for( auto e : ss){
      |                    ^~
a.cc:80:20: note: suggested alternatives:
/usr/include/c++/14/valarray:1265:5: note:   'std::end'
 1265 |     end(const valarray<_Tp>& __va) noexcept
      |     ^~~
/usr/include/c++/14/bits/fs_dir.h:613:3: note:   'std::filesystem::__cxx11::end'
  613 |   end(recursive_directory_iterator) noexcept
      |   ^~~
a.cc:81:16: error: request for member 'count' in 'ss', which is of non-class type 'int'
   81 |         if( ss.count({e.S,e.F}))
      |                ^~~~~