Language: C++

#include<bits/stdc++.h>
using namespace std;

int main(){
  string A, B, C;
  cin A << B << C;
  
  if (A.size == 5 || B.size == 7 || C.size == 5){
    cout << "YES" << endl;
  }
  else if (A.size == 7 || B.size == 5 || C.size == 5){
    cout << "YES"<< endl;
  }
  else if (A.size == 5 || B.size == 5 || C.size == 7){
    cout << "YES" << endl;
  }
  else {
    cout << "NO" << endl;
  }
}
      

Compiler output:
a.cc: In function 'int main()':
a.cc:6:6: error: expected ';' before 'A'
    6 |   cin A << B << C;
      |      ^~
      |      ;
a.cc:8:9: error: invalid use of member function 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size() const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; size_type = long unsigned int]' (did you forget the '()' ?)
    8 |   if (A.size == 5 || B.size == 7 || C.size == 5){
      |       ~~^~~~
      |             ()
a.cc:8:24: error: invalid use of member function 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size() const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; size_type = long unsigned int]' (did you forget the '()' ?)
    8 |   if (A.size == 5 || B.size == 7 || C.size == 5){
      |                      ~~^~~~
      |                            ()
a.cc:8:39: error: invalid use of member function 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size() const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; size_type = long unsigned int]' (did you forget the '()' ?)
    8 |   if (A.size == 5 || B.size == 7 || C.size == 5){
      |                                     ~~^~~~
      |                                           ()
a.cc:11:14: error: invalid use of member function 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size() const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; size_type = long unsigned int]' (did you forget the '()' ?)
   11 |   else if (A.size == 7 || B.size == 5 || C.size == 5){
      |            ~~^~~~
      |                  ()
a.cc:11:29: error: invalid use of member function 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size() const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; size_type = long unsigned int]' (did you forget the '()' ?)
   11 |   else if (A.size == 7 || B.size == 5 || C.size == 5){
      |                           ~~^~~~
      |                                 ()
a.cc:11:44: error: invalid use of member function 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size() const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; size_type = long unsigned int]' (did you forget the '()' ?)
   11 |   else if (A.size == 7 || B.size == 5 || C.size == 5){
      |                                          ~~^~~~
      |                                                ()
a.cc:14:14: error: invalid use of member function 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size() const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; size_type = long unsigned int]' (did you forget the '()' ?)
   14 |   else if (A.size == 5 || B.size == 5 || C.size == 7){
      |            ~~^~~~
      |                  ()
a.cc:14:29: error: invalid use of member function 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size() const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; size_type = long unsigned int]' (did you forget the '()' ?)
   14 |   else if (A.size == 5 || B.size == 5 || C.size == 7){
      |                           ~~^~~~
      |                                 ()
a.cc:14:44: error: invalid use of member function 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size() const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; size_type = long unsigned int]' (did you forget the '()' ?)
   14 |   else if (A.size == 5 || B.size == 5 || C.size == 7){
      |                                          ~~^~~~
      |                                                ()