Language: C++

#include <bits/stdc++.h>
using ll = long long;
#define FOR(i, k, n) for(ll i = (k); i < (n); i++)
#define FORe(i, k, n) for(ll i = (k); i <= (n); i++)
#define FORr(i, k, n) for(ll i = (k)-1; i > (n); i--)
#define FORre(i, k, n) for(ll i = (k)-1; i >= (n); i--)
#define REP(i, n) FOR(i, 0, n)
#define REPr(i, n) FORre(i, n, 0)
#define ALL(x) (x).begin(), (x).end()
#define ALLr(x) (x).rbegin(), (x).rend()
#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)
using namespace std;

const int INF = 1001001001;

using P = pair<ll, ll>;

int main(void){
  ll H, W, M;
  cin >> H >> W >> M;
  vector<ll> h(M), w(M);
  map<P, ll> mp;
  REP(i, M){
    cin >> h[i] >> w[i];
    h[i]--; w[i]--;
    mp[P(h[i], w[i])]++;
  }
  vector<ll> a(H, 0), b(W, 0);
  REP(i, M) a[h[i]]++, b[w[i]]++;

  ll c = *max_element(ALL(a));
  ll d = *max_element(ALL(b));
  vector<ll> p, q;
  REP(i, H) if(a[i] == c) p.emplace_back(i);
  REP(i, W) if(b[i] == d) q.emplace_back(i);
  
  ll n = p.size(), m = q.size();
  ll ans = c+d-1;
  REP(i, n) REP(j, m){
    if(mp[P(p[i], q[j]) == 0]){
      ans = c+d;
      break;
    }
  }
  cout << ans << endl;
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:41:25: error: no match for 'operator==' (operand types are 'P' {aka 'std::pair<long long int, long long int>'} and 'int')
   41 |     if(mp[P(p[i], q[j]) == 0]){
      |           ~~~~~~~~~~~~~ ^~ ~
      |           |                |
      |           |                int
      |           P {aka std::pair<long long int, long long int>}
In file included from /usr/include/c++/14/regex:68,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:181,
                 from a.cc:1:
/usr/include/c++/14/bits/regex.h:1103:5: note: candidate: 'template<class _BiIter> bool std::__cxx11::operator==(const sub_match<_BiIter>&, const sub_match<_BiIter>&)'
 1103 |     operator==(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1103:5: note:   template argument deduction/substitution failed:
a.cc:41:28: note:   'P' {aka 'std::pair<long long int, long long int>'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   41 |     if(mp[P(p[i], q[j]) == 0]){
      |                            ^
/usr/include/c++/14/bits/regex.h:1199:5: note: candidate: 'template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator==(__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&, const sub_match<_BiIter>&)'
 1199 |     operator==(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1199:5: note:   template argument deduction/substitution failed:
a.cc:41:28: note:   'P' {aka 'std::pair<long long int, long long int>'} is not derived from 'std::__cxx11::__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>'
   41 |     if(mp[P(p[i], q[j]) == 0]){
      |                            ^
/usr/include/c++/14/bits/regex.h:1274:5: note: candidate: 'template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator==(const sub_match<_BiIter>&, __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&)'
 1274 |     operator==(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1274:5: note:   template argument deduction/substitution failed:
a.cc:41:28: note:   'P' {aka 'std::pair<long long int, long long int>'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   41 |     if(mp[P(p[i], q[j]) == 0]){
      |                            ^
/usr/include/c++/14/bits/regex.h:1366:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator==(const typename std::iterator_traits<_Iter>::value_type*, const sub_match<_BiIter>&)'
 1366 |     operator==(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1366:5: note:   template argument deduction/substitution failed:
a.cc:41:28: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'int'
   41 |     if(mp[P(p[i], q[j]) == 0]){
      |                            ^
/usr/include/c++/14/bits/regex.h:1441:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator==(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type*)'
 1441 |     operator==(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1441:5: note:   template argument deduction/substitution failed:
a.cc:41:28: note:   'P' {aka 'std::pair<long long int, long long int>'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   41 |     if(mp[P(p[i], q[j]) == 0]){
      |                            ^
/usr/include/c++/14/bits/regex.h:1534:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator==(const typename std::iterator_traits<_Iter>::value_type&, const sub_match<_BiIter>&)'
 1534 |     operator==(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1534:5: note:   template argument deduction/substitution failed:
a.cc:41:28: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'int'
   41 |     if(mp[P(p[i], q[j]) == 0]){
      |                            ^
/usr/include/c++/14/bits/regex.h:1613:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator==(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type&)'
 1613 |     operator==(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1613:5: note:   template argument deduction/substitution failed:
a.cc:41:28: note:   'P' {aka 'std::pair<long long int, long long int>'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   41 |     if(mp[P(p[i], q[j]) == 0]){
      |                            ^
/usr/include/c++/14/bits/regex.h:2186:5: note: candidate: 'template<class _Bi_iter, class _Alloc> bool std::__cxx11::operator==(const match_results<_BiIter, _Alloc>&, const match_results<_BiIter, _Alloc>&)'
 2186 |     operator==(const match_results<_Bi_iter, _Alloc>& __m1,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:2186:5: note:   template argument deduction/substitution failed:
a.cc:41:28: note:   'P' {aka 'std::pair<long long int, long long int>'} is not derived from 'const std::__cxx11::match_results<_BiIter, _Alloc>'
   41 |     if(mp[P(p[i], q[j]) == 0]){
      |                            ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51:
/usr/include/c++/14/bits/stl_pair.h:1033:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator==(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1033 |     operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1033:5: note:   template argument deduction/substitution failed:
a.cc:41:28: note:   mismatched types 'const std::pair<_T1, _T2>' and 'int'
   41 |     if(mp[P(p[i], q[j]) == 0]){
      |                            ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:67:
/usr/include/c++/14/bits/stl_iterator.h:441:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator==(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  441 |     operator==(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:441:5: note:   template argument deduction/substitution failed:
a.cc:41:28: note:   'P' {aka 'std::pair<long long int, long long int>'} is not derived from 'const std::reverse_iterator<_Iterator>'
   41 |     if(mp[P(p[i], q[j]) == 0]){
      |                            ^
/usr/include/c++/14/bits/stl_iterator.h:486:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator==(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  486 |     operator==(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:486:5: note:   template argument deduction/substitution failed:
a.cc:41:28: note:   'P' {aka 'std::pair<long long int, long long int>'} is not derived from 'const std::reverse_iterator<_Iterator>'
   41 |     if(mp[P(p[i], q[j]) == 0]){
      |                            ^
/usr/include/c++/14/bits/stl_iterator.h:1667:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator==(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1667 |     operator==(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1667:5: note:   template argument deduction/substitution failed:
a.cc:41:28: note:   'P' {aka 'std::pair<long long int, long long int>'} is not derived from 'const std::move_iterator<_IteratorL>'
   41 |     if(mp[P(p[i], q[j]) == 0]){
      |                            ^
/usr/include/c++/14/bits/stl_iterator.h:1737:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator==(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1737 |     operator==(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1737:5: note:   template argument deduction/substitution failed:
a.cc:41:28: note:   'P' {aka 'std::pair<long long int, long long int>'} is not derived from 'const std::move_iterator<_IteratorL>'
   41 |     if(mp[P(p[i], q[j]) == 0]){
      |                            ^
In file included from /usr/include/c++/14/bits/char_traits.h:42,
                 from /usr/include/c++/14/string:42,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52:
/usr/include/c++/14/bits/postypes.h:192:5: note: candidate: 'template<class _StateT> bool std::operator==(const fpos<_StateT>&, const fpos<_StateT>&)'
  192 |     operator==(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/postypes.h:192:5: note:   template argument deduction/substitution failed:
a.cc:41:28: note:   'P' {aka 'std::pair<long long int, long long int>'} is not derived from 'const std::fpos<_StateT>'
   41 |     if(mp[P(p[i], q[j]) == 0]){
      |                            ^
In file included from /usr/include/c++/14/string:43:
/usr/include/c++/14/bits/allocator.h:235:5: note: candidate: 'template<class _T1, class _T2> bool std::operator==(const allocator<_CharT>&, const allocator<_T2>&)'
  235 |     operator==(const allocator<_T1>&, const allocator<_T2>&)
      |     ^~~~~~~~
/usr/include/c++/14/bits/allocator.h:235:5: note:   template argument deduction/substitution failed:
a.cc:41:28: note:   'P' {aka 'std::pair<long long int, long long int>'} is not derived from 'const std::allocator<_CharT>'
   41 |     if(mp[P(p[i], q[j]) == 0]){
      |                            ^
In file included from /usr/include/c++/14/bits/basic_string.h:47,
                 from /usr/include/c++/14/string:54:
/usr/include/c++/14/string_view:629:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator==(basic_string_view<_CharT, _Traits>, __type_identity_t<basic_string_vie