/in/foo.cc:1:2: error: stray '#' in program
 a#include<iostream>
  ^
/in/foo.cc:1:1: error: 'a' does not name a type
 a#include<iostream>
 ^
In file included from /usr/include/c++/6/cmath:43:0,
                 from /in/foo.cc:3:
/usr/include/c++/6/ext/type_traits.h:162:35: error: '__gnu_cxx::__is_null_pointer' declared as an 'inline' variable
   __is_null_pointer(std::nullptr_t)
                                   ^
/usr/include/c++/6/ext/type_traits.h:162:35: error: 'bool __gnu_cxx::__is_null_pointer' redeclared as different kind of symbol
/usr/include/c++/6/ext/type_traits.h:157:5: note: previous declaration 'template<class _Type> bool __gnu_cxx::__is_null_pointer(_Type)'
     __is_null_pointer(_Type)
     ^~~~~~~~~~~~~~~~~
/usr/include/c++/6/ext/type_traits.h:162:21: error: 'nullptr_t' is not a member of 'std'
   __is_null_pointer(std::nullptr_t)
                     ^~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:33:23: error: 'min' was not declared in this scope
  ans=min(min(ans1,ans2),ans3);
                       ^
/in/foo.cc:33:29: error: 'min' was not declared in this scope
  ans=min(min(ans1,ans2),ans3);
                             ^
/in/foo.cc:33:29: error: redeclaration of '<typeprefixerror>min'
/in/foo.cc:33:23: note: previous declaration '<typeprefixerror>min'
  ans=min(min(ans1,ans2),ans3);
                       ^