#include <iostream>
using namespace std;
class sum{
  int a;
  public:
  sum(int b){
    this-> a=b;
  }
  void display(){
    cout<<"The sum of 2 numbers is " <<a<<endl;
  }
  friend sum operator +(sum &s1, sum &s2);
};
sum operator +(sum &s1, sum &s2){
  int resum=s1.a+s2.a;
  sum c3(resum);
  cout << "The sum of number is " << endl;
  return c3;
}
int main(){
  sum s1(10), s2(23);
  s1.display();
  s2.display();
  sum s3 = s1 + s2;
  s3.display();
  return 0;
}