Language: C++

#include<bits/stdc++.h>
int main(){
    ll n,m,p[MAX],y[MAX],OUT_1[MAX],OUT_2[MAX],count[MAX];
    cin>>n>>m;
    vector<P>pairs(m);
    for(ll i=0;i<m;i++){
        cin>>pairs[i].first>>pairs[i].second;
        OUT_1[i]=pairs[i].first;
        count[pairs[i].second]=i;
    }
    sort(pairs.begin(),pairs.end());
    for(ll i=0;i<m;i++){
        cnt[pairs[i].first]++;
        OUT_2[count[pairs[i].second]]=cnt[pairs[i].first];
    }
    for(ll i=0;i<m;i++){
        printf("%06lld%06lld\n",OUT_1[i],OUT_2[i]);
    }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:3:5: error: 'll' was not declared in this scope
    3 |     ll n,m,p[MAX],y[MAX],OUT_1[MAX],OUT_2[MAX],count[MAX];
      |     ^~
a.cc:4:5: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    4 |     cin>>n>>m;
      |     ^~~
      |     std::cin
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:146,
                 from a.cc:1:
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:4:10: error: 'n' was not declared in this scope; did you mean 'yn'?
    4 |     cin>>n>>m;
      |          ^
      |          yn
a.cc:4:13: error: 'm' was not declared in this scope; did you mean 'tm'?
    4 |     cin>>n>>m;
      |             ^
      |             tm
a.cc:5:5: error: 'vector' was not declared in this scope
    5 |     vector<P>pairs(m);
      |     ^~~~~~
a.cc:5:5: note: suggested alternatives:
In file included from /usr/include/c++/14/vector:66,
                 from /usr/include/c++/14/functional:64,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:53:
/usr/include/c++/14/bits/stl_vector.h:428:11: note:   'std::vector'
  428 |     class vector : protected _Vector_base<_Tp, _Alloc>
      |           ^~~~~~
/usr/include/c++/14/vector:93:13: note:   'std::pmr::vector'
   93 |       using vector = std::vector<_Tp, polymorphic_allocator<_Tp>>;
      |             ^~~~~~
a.cc:5:12: error: 'P' was not declared in this scope
    5 |     vector<P>pairs(m);
      |            ^
a.cc:5:14: error: 'pairs' was not declared in this scope
    5 |     vector<P>pairs(m);
      |              ^~~~~
a.cc:6:11: error: expected ';' before 'i'
    6 |     for(ll i=0;i<m;i++){
      |           ^~
      |           ;
a.cc:6:16: error: 'i' was not declared in this scope
    6 |     for(ll i=0;i<m;i++){
      |                ^
a.cc:8:9: error: 'OUT_1' was not declared in this scope
    8 |         OUT_1[i]=pairs[i].first;
      |         ^~~~~
a.cc:9:9: error: 'count' was not declared in this scope; did you mean 'std::count'?
    9 |         count[pairs[i].second]=i;
      |         ^~~~~
      |         std::count
In file included from /usr/include/c++/14/algorithm:86,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51:
/usr/include/c++/14/pstl/glue_algorithm_defs.h:101:1: note: 'std::count' declared here
  101 | count(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value);
      | ^~~~~
a.cc:11:5: error: 'sort' was not declared in this scope; did you mean 'std::sort'?
   11 |     sort(pairs.begin(),pairs.end());
      |     ^~~~
      |     std::sort
/usr/include/c++/14/pstl/glue_algorithm_defs.h:296:1: note: 'std::sort' declared here
  296 | sort(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last);
      | ^~~~
a.cc:12:11: error: expected ';' before 'i'
   12 |     for(ll i=0;i<m;i++){
      |           ^~
      |           ;
a.cc:12:16: error: 'i' was not declared in this scope
   12 |     for(ll i=0;i<m;i++){
      |                ^
a.cc:13:9: error: 'cnt' was not declared in this scope; did you mean 'int'?
   13 |         cnt[pairs[i].first]++;
      |         ^~~
      |         int
a.cc:14:9: error: 'OUT_2' was not declared in this scope
   14 |         OUT_2[count[pairs[i].second]]=cnt[pairs[i].first];
      |         ^~~~~
a.cc:14:15: error: 'count' was not declared in this scope; did you mean 'std::count'?
   14 |         OUT_2[count[pairs[i].second]]=cnt[pairs[i].first];
      |               ^~~~~
      |               std::count
/usr/include/c++/14/pstl/glue_algorithm_defs.h:101:1: note: 'std::count' declared here
  101 | count(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value);
      | ^~~~~
a.cc:16:11: error: expected ';' before 'i'
   16 |     for(ll i=0;i<m;i++){
      |           ^~
      |           ;
a.cc:16:16: error: 'i' was not declared in this scope
   16 |     for(ll i=0;i<m;i++){
      |                ^
a.cc:17:33: error: 'OUT_1' was not declared in this scope
   17 |         printf("%06lld%06lld\n",OUT_1[i],OUT_2[i]);
      |                                 ^~~~~
a.cc:17:42: error: 'OUT_2' was not declared in this scope
   17 |         printf("%06lld%06lld\n",OUT_1[i],OUT_2[i]);
      |                                          ^~~~~