#include <iostream>
#include <iomanip>
using namespace std;
class Arithmetic{
    protected:
    int op;
    public:
    void display(){
        cin>>op;
    }
};
class Operation : public Arithmetic{
    protected:
    int a,b;
    public:
    void display1(){
        cin>>a>>b;
        if(op<=0){
            cout<<"Invalid input";
        }
        else if(op==1){
            cout<<a+b;
        }
        else if(op==2){
            cout<<a-b;
        }
        else if(op==3){
            cout<<a*b;
        }
        else if(op==4){
            if(a==0 || b==0){
                cout<<"Division by zero";
                return 0;
            }
            else{
                cout<<a/b;
            }
        }
    }
};
int main(){
    Operation o;
    o.display();
    o.display1();
    return 0;
}