Language: C++

#include <bits/stdc++.h>
using namespace std;
 
int main() {
  int n,x,c_point=0,count=0;
  cin>>n;
  vector<int> a(n);
  for(int i=0;i<n;i++){
    cin>>a.at(i)-1;
  }
  while(c_point!=1){
    if(a.at(c_point)==n){
      count=-1;
      c_point=1;
    }
    else{
      x=c_point;
      c_point=a.at(c_point);
      a.at(x)=n;
      count++;
    }
  }
  cout<<count<<endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:8: error: no match for 'operator>>' (operand types are 'std::istream' {aka 'std::basic_istream<char>'} and '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'})
    9 |     cin>>a.at(i)-1;
      |     ~~~^~~~~~~~~~~
      |     |           |
      |     |           __gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type {aka int}
      |     std::istream {aka std::basic_istream<char>}
In file included 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,
                 from a.cc:1:
/usr/include/c++/14/istream:170:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(bool&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  170 |       operator>>(bool& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:170:7: note:   conversion of argument 1 would be ill-formed:
a.cc:9:17: error: cannot bind non-const lvalue reference of type 'bool&' to a value of type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
    9 |     cin>>a.at(i)-1;
      |          ~~~~~~~^~
/usr/include/c++/14/istream:174:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(short int&) [with _CharT = char; _Traits = std::char_traits<char>]' (near match)
  174 |       operator>>(short& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:174:7: note:   conversion of argument 1 would be ill-formed:
a.cc:9:17: error: cannot bind non-const lvalue reference of type 'short int&' to a value of type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
    9 |     cin>>a.at(i)-1;
      |          ~~~~~~~^~
/usr/include/c++/14/istream:177:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(short unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  177 |       operator>>(unsigned short& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:177:7: note:   conversion of argument 1 would be ill-formed:
a.cc:9:17: error: cannot bind non-const lvalue reference of type 'short unsigned int&' to a value of type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
    9 |     cin>>a.at(i)-1;
      |          ~~~~~~~^~
/usr/include/c++/14/istream:181:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(int&) [with _CharT = char; _Traits = std::char_traits<char>]' (near match)
  181 |       operator>>(int& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:181:7: note:   conversion of argument 1 would be ill-formed:
a.cc:9:17: error: cannot bind non-const lvalue reference of type 'int&' to an rvalue of type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
    9 |     cin>>a.at(i)-1;
      |          ~~~~~~~^~
/usr/include/c++/14/istream:184:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  184 |       operator>>(unsigned int& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:184:7: note:   conversion of argument 1 would be ill-formed:
a.cc:9:17: error: cannot bind non-const lvalue reference of type 'unsigned int&' to a value of type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
    9 |     cin>>a.at(i)-1;
      |          ~~~~~~~^~
/usr/include/c++/14/istream:188:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  188 |       operator>>(long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:188:7: note:   conversion of argument 1 would be ill-formed:
a.cc:9:17: error: cannot bind non-const lvalue reference of type 'long int&' to a value of type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
    9 |     cin>>a.at(i)-1;
      |          ~~~~~~~^~
/usr/include/c++/14/istream:192:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  192 |       operator>>(unsigned long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:192:7: note:   conversion of argument 1 would be ill-formed:
a.cc:9:17: error: cannot bind non-const lvalue reference of type 'long unsigned int&' to a value of type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
    9 |     cin>>a.at(i)-1;
      |          ~~~~~~~^~
/usr/include/c++/14/istream:199:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  199 |       operator>>(long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:199:7: note:   conversion of argument 1 would be ill-formed:
a.cc:9:17: error: cannot bind non-const lvalue reference of type 'long long int&' to a value of type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
    9 |     cin>>a.at(i)-1;
      |          ~~~~~~~^~
/usr/include/c++/14/istream:203:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  203 |       operator>>(unsigned long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:203:7: note:   conversion of argument 1 would be ill-formed:
a.cc:9:17: error: cannot bind non-const lvalue reference of type 'long long unsigned int&' to a value of type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
    9 |     cin>>a.at(i)-1;
      |          ~~~~~~~^~
/usr/include/c++/14/istream:219:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(float&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  219 |       operator>>(float& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:219:7: note:   conversion of argument 1 would be ill-formed:
a.cc:9:17: error: cannot bind non-const lvalue reference of type 'float&' to a value of type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
    9 |     cin>>a.at(i)-1;
      |          ~~~~~~~^~
/usr/include/c++/14/istream:223:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(double&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  223 |       operator>>(double& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:223:7: note:   conversion of argument 1 would be ill-formed:
a.cc:9:17: error: cannot bind non-const lvalue reference of type 'double&' to a value of type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
    9 |     cin>>a.at(i)-1;
      |          ~~~~~~~^~
/usr/include/c++/14/istream:227:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long double&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  227 |       operator>>(long double& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:227:7: note:   conversion of argument 1 would be ill-formed:
a.cc:9:17: error: cannot bind non-const lvalue reference of type 'long double&' to a value of type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
    9 |     cin>>a.at(i)-1;
      |          ~~~~~~~^~
/usr/include/c++/14/istream:328:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(void*&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  328 |       operator>>(void*& __p)
      |       ^~~~~~~~
/usr/include/c++/14/istream:328:7: note:   conversion of argument 1 would be ill-formed:
a.cc:9:17: error: invalid conversion from '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'} to 'void*' [-fpermissive]
    9 |     cin>>a.at(i)-1;
      |          ~~~~~~~^~
      |                 |
      |                 __gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type {aka int}
a.cc:9:17: error: cannot bind rvalue '(void*)((long int)(a.std::vector<int>::at(((std::vector<int>::size_type)i)) - 1))' to 'void*&'
/usr/include/c++/14/istream:122:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(__istream_type& (*)(__istream_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  122 |       operator>>(__istream_type& (*__pf)(__istream_type&))
      |       ^~~~~~~~
/usr/include/c++/14/istream:122:7: note:   conversion of argument 1 would be ill-formed:
a.cc:9:17: error: invalid conversion from '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'} to 'std::basic_istream<char>::__istream_type& (*)(std::basic_istream<char>::__istream_type&)' {aka 'std::basic_istream<char>& (*)(std::basic_istream<char>&)'} [-fpermissive