Help me in solving USR2V2 problem

My issue

if we want the input at different lines, and on using “endl” operator it shows compilation error, why?

My code

#include <iostream>
using namespace std;

int main() {

  int a,b;
  cout<< "Sum is: " << a+b<<endl;
  cout<< "Difference is: " << a-b;

  return 0;

Learning course: Learn C++
Problem Link: CodeChef: Practical coding for everyone

cin is for taking input from the user.
you cannot use it like this.