Language: C++

#pragma comment(linker, "/STACK:1024000000,1024000000")
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <limits.h>
#include <assert.h>
#include <math.h>
#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <string>
#include <bitset>
#include <vector>
using namespace std;

#define LL long long

#define fi first
#define se second
#define lson l,mid,id<<1
#define rson mid+1,r,id<<1|1
#define ls id<<1
#define rs id<<1|1
#define MID(a,b) (((a)+(b))>>1)
#define maxx(a,b) ((a)<(b)?(b):(a))
#define minx(a,b) ((a)<(b)?(a):(b))
#define absx(a) ((a)<0?-(a):(a))
#define mk(a,b) make_pair(a,b)
#define pb(a) push_back(a)
#define itr iterator
#define lowbit(x) ((x)&-(x))

typedef unsigned LL ULL;
typedef unsigned uint;
typedef map<int,int> mii;
typedef pair<int,int> pii;
typedef pair<double,double> pdd;
typedef pair<LL,LL> pLL;

template< typename T > inline void read(T &x) {
    bool f; char ch; f=0; x=0; ch=getchar();
    while(ch<'0' || ch>'9') {if(ch=='-') f=1; ch=getchar();}
    while(ch>='0' && ch<='9') {x=x*10+ch-'0'; ch=getchar();}
    if(f) x=-x;
}

template< typename T > inline void Max(T &a, T b) {if(a<b) a=b;}
template< typename T > inline void Min(T &a, T b) {if(b<a) a=b;}
template< typename T > inline T Abs(T a) {if(a<0) return -a; else return a;}

const double pi=(double) acos(-1.0);
const int MOD=(int) 1e9+7;
const int INF=(int) 0x3f3f3f3f;
const LL  LINF=(LL) INF<<32|INF;
const int SINF=(uint) ~0>>1;
const LL  SLINF=(ULL) (-1)>>1;
const double DINF=(double) 1e50;
const double eps=(double) 1e-8;
const int maxn=(int) 2000+20;
const int maxm=(int) 1e6+20;
const int maxk=(int) 5e2+20;

inline int sig(double x) {return x<-eps?-1:x>eps;}

//--------------start------------------

void work()
{
    int R,G;
    cout >>R >>G;
    cout <<G-R+G <<endl;
}

//--------------end--------------------

int main()
{
#ifdef yukihana0416
freopen("in.txt","r",stdin);
//freopen("out.txt","w",stdout);
#endif // yukihana0416
    work();
    return 0;
}


Compiler output:
a.cc: In function 'void work()':
a.cc:74:10: error: no match for 'operator>>' (operand types are 'std::ostream' {aka 'std::basic_ostream<char>'} and 'int')
   74 |     cout >>R >>G;
      |     ~~~~ ^~~
      |     |      |
      |     |      int
      |     std::ostream {aka std::basic_ostream<char>}
a.cc:74:10: note: candidate: 'operator>>(int, int)' (built-in)
   74 |     cout >>R >>G;
      |     ~~~~~^~~
a.cc:74:10: note:   no known conversion for argument 1 from 'std::ostream' {aka 'std::basic_ostream<char>'} to 'int'
In file included from /usr/include/c++/14/string:55,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:9:
/usr/include/c++/14/bits/basic_string.tcc:835:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::basic_istream<_CharT, _Traits>& std::operator>>(basic_istream<_CharT, _Traits>&, __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
  835 |     operator>>(basic_istream<_CharT, _Traits>& __in,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.tcc:835:5: note:   template argument deduction/substitution failed:
a.cc:74:12: note:   'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
   74 |     cout >>R >>G;
      |            ^
In file included from /usr/include/c++/14/bits/memory_resource.h:38,
                 from /usr/include/c++/14/string:68:
/usr/include/c++/14/cstddef:131:5: note: candidate: 'template<class _IntegerType> constexpr std::__byte_op_t<_IntegerType> std::operator>>(byte, _IntegerType)'
  131 |     operator>>(byte __b, _IntegerType __shift) noexcept
      |     ^~~~~~~~
/usr/include/c++/14/cstddef:131:5: note:   template argument deduction/substitution failed:
a.cc:74:5: note:   cannot convert 'std::cout' (type 'std::ostream' {aka 'std::basic_ostream<char>'}) to type 'std::byte'
   74 |     cout >>R >>G;
      |     ^~~~
In file included from /usr/include/c++/14/istream:1109,
                 from /usr/include/c++/14/iostream:42:
/usr/include/c++/14/bits/istream.tcc:978:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_istream<_CharT, _Traits>& std::operator>>(basic_istream<_CharT, _Traits>&, _CharT&)'
  978 |     operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c)
      |     ^~~~~~~~
/usr/include/c++/14/bits/istream.tcc:978:5: note:   template argument deduction/substitution failed:
a.cc:74:12: note:   'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
   74 |     cout >>R >>G;
      |            ^
/usr/include/c++/14/istream:849:5: note: candidate: 'template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(basic_istream<char, _Traits>&, unsigned char&)'
  849 |     operator>>(basic_istream<char, _Traits>& __in, unsigned char& __c)
      |     ^~~~~~~~
/usr/include/c++/14/istream:849:5: note:   template argument deduction/substitution failed:
a.cc:74:12: note:   'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<char, _Traits>'
   74 |     cout >>R >>G;
      |            ^
/usr/include/c++/14/istream:854:5: note: candidate: 'template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(basic_istream<char, _Traits>&, signed char&)'
  854 |     operator>>(basic_istream<char, _Traits>& __in, signed char& __c)
      |     ^~~~~~~~
/usr/include/c++/14/istream:854:5: note:   template argument deduction/substitution failed:
a.cc:74:12: note:   'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<char, _Traits>'
   74 |     cout >>R >>G;
      |            ^
/usr/include/c++/14/istream:896:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_istream<_CharT, _Traits>& std::operator>>(basic_istream<_CharT, _Traits>&, _CharT*)'
  896 |     operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s)
      |     ^~~~~~~~
/usr/include/c++/14/istream:896:5: note:   template argument deduction/substitution failed:
a.cc:74:12: note:   'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
   74 |     cout >>R >>G;
      |            ^
/usr/include/c++/14/istream:939:5: note: candidate: 'template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(basic_istream<char, _Traits>&, unsigned char*)'
  939 |     operator>>(basic_istream<char, _Traits>& __in, unsigned char* __s)
      |     ^~~~~~~~
/usr/include/c++/14/istream:939:5: note:   template argument deduction/substitution failed:
a.cc:74:12: note:   'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<char, _Traits>'
   74 |     cout >>R >>G;
      |            ^
/usr/include/c++/14/istream:945:5: note: candidate: 'template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(basic_istream<char, _Traits>&, signed char*)'
  945 |     operator>>(basic_istream<char, _Traits>& __in, signed char* __s)
      |     ^~~~~~~~
/usr/include/c++/14/istream:945:5: note:   template argument deduction/substitution failed:
a.cc:74:12: note:   'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<char, _Traits>'
   74 |     cout >>R >>G;
      |            ^
/usr/include/c++/14/istream:1099:5: note: candidate: 'template<class _Istream, class _Tp> _Istream&& std::operator>>(_Istream&&, _Tp&&)'
 1099 |     operator>>(_Istream&& __is, _Tp&& __x)
      |     ^~~~~~~~
/usr/include/c++/14/istream:1099:5: note:   template argument deduction/substitution failed:
/usr/include/c++/14/istream: In substitution of 'template<class _Istream, class _Tp> _Istream&& std::operator>>(_Istream&&, _Tp&&) [with _Istream = std::basic_ostream<char>&; _Tp = int&]':
a.cc:74:12:   required from here
   74 |     cout >>R >>G;
      |            ^
/usr/include/c++/14/istream:1099:5: error: no type named 'type' in 'struct std::enable_if<false, void>'
 1099 |     operator>>(_Istream&& __is, _Tp&& __x)
      |     ^~~~~~~~
In file included from a.cc:16:
/usr/include/c++/14/bitset:1597:5: note: candidate: 'template<class _CharT, class _Traits, long unsigned int _Nb> std::basic_istream<_CharT, _Traits>& std::operator>>(basic_istream<_CharT, _Traits>&, bitset<_Nb>&)'
 1597 |     operator>>(std::basic_istream<_CharT, _Traits>& __is, bitset<_Nb>& __x)
      |     ^~~~~~~~
/usr/include/c++/14/bitset:1597:5: note:   template argument deduction/substitution failed:
a.cc:74:12: note:   'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
   74 |     cout >>R >>G;
      |            ^