/in/foo.cc:3:1: error: 'pl' does not name a type
 pl DC(int l,int r)
 ^~
/in/foo.cc: In function 'int main()':
/in/foo.cc:23:1: error: 'ios' has not been declared
 ios::sync_with_stdio(false);
 ^~~
/in/foo.cc:24:1: error: 'cin' was not declared in this scope
 cin>>n;
 ^~~
/in/foo.cc:27:1: error: 'cout' was not declared in this scope
 cout<<DC(0,n-1).first<<endl;
 ^~~~
/in/foo.cc:27:15: error: 'DC' was not declared in this scope
 cout<<DC(0,n-1).first<<endl;
               ^
/in/foo.cc:27:24: error: 'endl' was not declared in this scope
 cout<<DC(0,n-1).first<<endl;
                        ^~~~