#include<iostream>
using namespace std;
class forgetcode;
class forgetcode1
{
    int x;
    public:
    void setvalue(int i)
    {
        x=i;
    }
     void operation(forgetcode1,forgetcode);
};
    class forgetcode
    {
        int a;
        public:
        void setvalue(int i)
        {
            a=i;
        }
       friend void forgetcode1::operation(forgetcode1 m,forgetcode n);
        
       
    };
        void forgetcode1::operation( forgetcode1 m,forgetcode n)
         {
            if(m.x>=n.a)
            cout<<"m:"<<m.x-n.a;
        else
            cout<<"n:"<<m.x+n.a;
        }
               
    int main()
{
    forgetcode f;
    f.setvalue(10);
    forgetcode1 f1;
    f1.setvalue(20);
   f1.operation(f1,f);
    return 0;
}