Language: C++

#include <bits/stdc++.h>

#define REP(i, n) for(int i = 0; i < n; ++i)
#define REPR(i, n) for(int i = n; i >= 0; --i)
#define FOR(i, m, n) for(int i = m; i < n; ++i)
#define FORR(i, m, n) for(int i = m; i >= n; --i)
#define SORT(v, n) sort(v, v+n);
#define VSORT(v) sort(v.begin(), v.end());
#define llong long long
#define pb(a) push_back(a)

#define INF 999999999

using namespace std;

typedef pair<int, int> P;
typedef pair<llong, llong> LP;
typedef pair<int, P> PP;
typedef pair<llong, LP> LPP;

int dx[]={1, -1, 0, 0, 0};
int dy[]={0, 0, 1, -1, 0};

int main(){
    cin.tie(0); //cinとcoutの同期切り
    ios::sync_with_stdio(false); //iostreamとstdioの同期切り

    int A, B;
    cin << A << B;

    cout << max(A+B, max(A-B, A*B)) << endl;

    return 0;
}

/*****************************************************************************/
/*****   1秒間で処理できるfor文ループの回数                                 *****/
/*****   → 10^8 = 100,000,000 回程度                                      *****/
/*****                                                                   *****/
/*****   sort(a, a+N, greater<int>()); // a[0:N) を大きい順にソート        *****/
/*****                                                                   *****/
/*****                                                                   *****/
/*****   std::cout << std::setprecision(2) << 3.0; // "3"                *****/
/*****   std::cout << std::fixed;                                        *****/
/*****   std::cout << std::setprecision(2) << 3.0; // "3.00"             *****/
/*****                                                                   *****/
/*****************************************************************************/

Compiler output:
a.cc: In function 'int main()':
a.cc:29:9: error: no match for 'operator<<' (operand types are 'std::istream' {aka 'std::basic_istream<char>'} and 'int')
   29 |     cin << A << B;
      |     ~~~ ^~ ~
      |     |      |
      |     |      int
      |     std::istream {aka std::basic_istream<char>}
a.cc:29:9: note: candidate: 'operator<<(int, int)' (built-in)
   29 |     cin << A << B;
      |     ~~~~^~~~
a.cc:29:9: note:   no known conversion for argument 1 from 'std::istream' {aka 'std::basic_istream<char>'} to '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:1715:5: note: candidate: 'template<class _Ch_type, class _Ch_traits, class _Bi_iter> std::basic_ostream<_CharT, _Traits>& std::__cxx11::operator<<(std::basic_ostream<_CharT, _Traits>&, const sub_match<_Bi_iter>&)'
 1715 |     operator<<(basic_ostream<_Ch_type, _Ch_traits>& __os,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1715:5: note:   template argument deduction/substitution failed:
a.cc:29:12: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
   29 |     cin << A << B;
      |            ^
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:41:
/usr/include/c++/14/cstddef:125:5: note: candidate: 'template<class _IntegerType> constexpr std::__byte_op_t<_IntegerType> std::operator<<(byte, _IntegerType)'
  125 |     operator<<(byte __b, _IntegerType __shift) noexcept
      |     ^~~~~~~~
/usr/include/c++/14/cstddef:125:5: note:   template argument deduction/substitution failed:
a.cc:29:5: note:   cannot convert 'std::cin' (type 'std::istream' {aka 'std::basic_istream<char>'}) to type 'std::byte'
   29 |     cin << A << B;
      |     ^~~
In file included from /usr/include/c++/14/bits/basic_string.h:47,
                 from /usr/include/c++/14/string:54,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52:
/usr/include/c++/14/string_view:763:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, basic_string_view<_CharT, _Traits>)'
  763 |     operator<<(basic_ostream<_CharT, _Traits>& __os,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:763:5: note:   template argument deduction/substitution failed:
a.cc:29:12: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
   29 |     cin << A << B;
      |            ^
/usr/include/c++/14/bits/basic_string.h:4077:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 4077 |     operator<<(basic_ostream<_CharT, _Traits>& __os,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:4077:5: note:   template argument deduction/substitution failed:
a.cc:29:12: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
   29 |     cin << A << B;
      |            ^
/usr/include/c++/14/bitset:1687:5: note: candidate: 'template<class _CharT, class _Traits, long unsigned int _Nb> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, const bitset<_Nb>&)'
 1687 |     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
      |     ^~~~~~~~
/usr/include/c++/14/bitset:1687:5: note:   template argument deduction/substitution failed:
a.cc:29:12: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
   29 |     cin << A << B;
      |            ^
In file included from /usr/include/c++/14/bits/ios_base.h:46,
                 from /usr/include/c++/14/streambuf:43,
                 from /usr/include/c++/14/bits/streambuf_iterator.h:35,
                 from /usr/include/c++/14/iterator:66,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:54:
/usr/include/c++/14/system_error:339:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, const error_code&)'
  339 |     operator<<(basic_ostream<_CharT, _Traits>& __os, const error_code& __e)
      |     ^~~~~~~~
/usr/include/c++/14/system_error:339:5: note:   template argument deduction/substitution failed:
a.cc:29:12: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
   29 |     cin << A << B;
      |            ^
In file included from /usr/include/c++/14/memory:80,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:56:
/usr/include/c++/14/bits/shared_ptr.h:70:5: note: candidate: 'template<class _Ch, class _Tr, class _Tp, __gnu_cxx::_Lock_policy _Lp> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, const __shared_ptr<_Tp, _Lp>&)'
   70 |     operator<<(std::basic_ostream<_Ch, _Tr>& __os,
      |     ^~~~~~~~
/usr/include/c++/14/bits/shared_ptr.h:70:5: note:   template argument deduction/substitution failed:
a.cc:29:12: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
   29 |     cin << A << B;
      |            ^
In file included from /usr/include/c++/14/istream:41,
                 from /usr/include/c++/14/sstream:40,
                 from /usr/include/c++/14/complex:45,
                 from /usr/include/c++/14/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:127:
/usr/include/c++/14/ostream:563:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, _CharT)'
  563 |     operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c)
      |     ^~~~~~~~
/usr/include/c++/14/ostream:563:5: note:   template argument deduction/substitution failed:
a.cc:29:12: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
   29 |     cin << A << B;
      |            ^
/usr/include/c++/14/ostream:573:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, char)'
  573 |     operator<<(basic_ostream<_CharT, _Traits>& __out, char __c)
      |     ^~~~~~~~
/usr/include/c++/14/ostream:573:5: note:   template argument deduction/substitution failed:
a.cc:29:12: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
   29 |     cin << A << B;
      |            ^
/usr/include/c++/14/ostream:579:5: note: candidate: 'template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(basic_ostream<char, _Traits>&, char)'
  579 |     operator<<(basic_ostream<char, _Traits>& __out, char __c)
      |     ^~~~~~~~
/usr/include/c++/14/ostream:579:5: note:   template argument deduction/substitution failed:
a.cc:29:12: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<char, _Traits>'
   29 |     cin << A << B;
      |            ^
/usr/include/c++/14/ostream:590:5: note: candidate: 'template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(basic_ostream<char, _Traits>&, signed char)'
  590 |     operator<<(basic_ostream<char, _Traits>& __out, signed char __c)
      |     ^~~~~~~~
/usr/include/c++/14/ostream:590:5: note:   template argument deduction/substitution failed:
a.cc:29:12: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<char, _Traits>'
   29 |     cin << A << B;
      |            ^
/usr/include/c++/14/ostream:595:5: note: candidate: 'template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(basic_ostream<char, _Traits>&, unsigned char)'
  595 |     operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c)
      |     ^~~~~~~~
/usr/include/c++/14/ostream:595:5: note:   template argument deduction/substitution failed:
a.cc:29:12: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<char, _Traits>'
   29 |     cin << A << B;
      |            ^
/usr/include/c++/14/ostream:654:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, const _CharT*)'
  654 |     operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s)
      |     ^~~~~~~~
/usr/include/c++/14/ostream:654:5: note:   template argument deduction/substitution failed:
a.cc:29:12: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
   29 |     cin << A << B;
      |            ^
In file included from /usr/include/c++/14/ostream:1022:
/usr/include/c++/14/bits/ostream.tcc:307:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, const char*)'
  307 |     operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s)
      |     ^~~~~~~~
/usr/include/c++/14/bits/ostream.tcc:307:5: note:   template argument deduction/substitution failed:
a.cc:29:12: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
   29 |     cin << A << B;
      |            ^
/usr/include/c++/14/ostream:671:5: note: candidate: 'template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(basic_ostream<char, _Traits>&, const char*)'
  671 |     operator<<(basic_ostream<char, _Traits>& __out, const char* __s)
      |     ^~~~~~~~
/usr/include/c++/14/ostream:671:5: note:   template argument deduction/substitution failed:
a.cc:29:12: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<char, _Traits>'
   29 |     cin << A << B;
      |            ^
/usr/incl