Language: C++

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#define ll              long long
#define pb              push_back
#define ppb             pop_back
#define endl            '\n'
#define mii             map<ll,ll>
#define pii             pair<ll,ll>
#define vi              vector<ll>
#define vs              vector<string>
#define all(a)          (a).begin(),(a).end()
#define F               first
#define S               second
#define sz(x)           (ll)x.size()
#define hell            1000000007
#define inf             (ll)1e18 + 5
#define PI              (double)3.14159265358979323844
#define DECIMAL(n)      cout << fixed << setprecision(n);
#define rep(i,a,b)      for (ll i=a;i<b;i++)
#define repr(i,a,b)     for (ll i=a-1;i>=b;i--)
#define bitcount(a)     (ll)__builtin_popcount(a)
#define lbnd            lower_bound
#define ubnd            upper_bound
#define mp              make_pair
#define ios             ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define ordered_set     tree<ll, null_type,less<ll>, rb_tree_tag,tree_order_statistics_node_update>
#define trace(...)      __f(#__VA_ARGS__, __VA_ARGS__)

template <typename Arg1>
void __f(const char* name, Arg1&& arg1){
    std::cerr << name << " : " << arg1 << endl;
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args){
    const char* comma = strchr(names + 1, ',');std::cerr.write(names, comma - names) << " : " << arg1<<" | ";__f(comma+1, args...);
}

using namespace std;
using namespace __gnu_pbds;

/*----------------------Graph Moves----------------*/
//const int fx[]={+1,-1,+0,+0};
//const int fy[]={+0,+0,+1,-1};
//const int fx[]={+0,+0,+1,-1,-1,+1,-1,+1};   // Kings Move
//const int fy[]={-1,+1,+0,+0,+1,+1,-1,-1};  // Kings Move
//const int fx[]={-2, -2, -1, -1,  1,  1,  2,  2};  // Knights Move
//const int fy[]={-1,  1, -2,  2, -2,  2, -1,  1}; // Knights Move
/*------------------------------------------------*/

//primes for hashing 937,991,1013,1409,1741

void solve() {
    string s;
  cin>>s;
  if (s[1]=='R){
      cout<<"ABC"<<endl;
      }
      else{
        cout<<"ARC"<<endl;
      }
}

signed main() {
    ios
    ll test=1;
    //cin>>test;
    while (test--) solve();
    return 0;
}

Compiler output:
a.cc:57:13: warning: missing terminating ' character
   57 |   if (s[1]=='R){
      |             ^
a.cc:57:13: error: missing terminating ' character
   57 |   if (s[1]=='R){
      |             ^~~~
a.cc: In function 'void solve()':
a.cc:57:11: error: no match for 'operator==' (operand types are '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'} and 'std::basic_ostream<char>')
   57 |   if (s[1]=='R){
a.cc:57:11: note: candidate: 'operator==(int, int)' (built-in)
a.cc:57:11: note:   no known conversion for argument 2 from 'std::basic_ostream<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: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:8:25: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
    8 | #define endl            '\n'
      |                         ^~~~
a.cc:58:20: note: in expansion of macro 'endl'
   58 |       cout<<"ABC"<<endl;
      |                    ^~~~
/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:8:25: note:   mismatched types 'std::__cxx11::__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
    8 | #define endl            '\n'
      |                         ^~~~
a.cc:58:20: note: in expansion of macro 'endl'
   58 |       cout<<"ABC"<<endl;
      |                    ^~~~
/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:8:25: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
    8 | #define endl            '\n'
      |                         ^~~~
a.cc:58:20: note: in expansion of macro 'endl'
   58 |       cout<<"ABC"<<endl;
      |                    ^~~~
/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:8:25: note:   'std::basic_ostream<char>' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
    8 | #define endl            '\n'
      |                         ^~~~
a.cc:58:20: note: in expansion of macro 'endl'
   58 |       cout<<"ABC"<<endl;
      |                    ^~~~
/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:8:25: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
    8 | #define endl            '\n'
      |                         ^~~~
a.cc:58:20: note: in expansion of macro 'endl'
   58 |       cout<<"ABC"<<endl;
      |                    ^~~~
/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:8:25: note:   'std::basic_ostream<char>' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
    8 | #define endl            '\n'
      |                         ^~~~
a.cc:58:20: note: in expansion of macro 'endl'
   58 |       cout<<"ABC"<<endl;
      |                    ^~~~
/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:8:25: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
    8 | #define endl            '\n'
      |                         ^~~~
a.cc:58:20: note: in expansion of macro 'endl'
   58 |       cout<<"ABC"<<endl;
      |                    ^~~~
/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:8:25: note:   mismatched types 'const std::__cxx11::match_results<_BiIter, _Alloc>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
    8 | #define endl            '\n'
      |                         ^~~~
a.cc:58:20: note: in expansion of macro 'endl'
   58 |       cout<<"ABC"<<endl;
      |                    ^~~~
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:8:25: note:   mismatched types 'const std::pair<_T1, _T2>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
    8 | #define endl            '\n'
      |                         ^~~~
a.cc:58:20: note: in expansion of macro 'endl'
   58 |       cout<<"ABC"<<endl;
      |                    ^~~~
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:8:25: note:   mismatched types 'const std::reverse_iterator<_Iterator>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
    8 | #define endl            '\n'
      |                         ^~~~
a.cc:58:20: note: in expansion of macro 'endl'
   58 |       cout<<"ABC"<<endl;
      |                    ^~~~
/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:8:25: note:   mismatched types 'const std::reverse_iterator<_Iterator>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
    8 | #define endl            '\n'
      |                         ^~~~
a.cc:58:20: note: in expansion of macro 'endl'
   58 |       cout<<"ABC"<<endl;
      |                    ^~~~
/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:8:25: note:   mismatched types 'const std::move_iterator<_IteratorL>' and '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'}
    8 | #define endl            '\n'
      |                         ^~~~
a.cc:58:20: note: in expansion of macro 'endl'
   58 |       cout<<"ABC"<<endl;
      |                    ^~~~
/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:8:25: note:   mismatch