#include<iostream>
#include <string>
using namespace std;

class Calculator {
    
    void compute(int t, int a, int b){
        perform0p(t,(double)a,(double)b);
    }
    void compute(int t, double a, double b){
        perform0p(t,a,b);
    }
    
    
    void perform0p(int t, double a,double b){
        cout <<"Invallid input"<<endl;
        return ;
    }
    switch(t){
        case 1:
        cout <<a+b<<endl;
        break;
        case 2:
        cout <<a-b<<endl;
        break;
        case 3:
        cout <<a*b<<endl;
        break;
        case 4:
        if(a==0 || b==0){
            cout <<"Division by zero"<<endl;
        }
        else {
            cout <<a/b<<endl;
        }
        break;
        default:
        cout<<"Invalid input"<<endl;
        break;
    }
};
int main(){
    string line1,line2,line3;
    if(!(cin>>line1>>line2>>line3))
    return 0;
    
    int t= stoi(line1);
    Calculator calc;
    
    if(line2.find('.')!=string::npos || line3.find('.')!=string::npos){
        double a = stod(line2);
        double b= stod(line3);
        calc.compute(t,a,b);
    }
    else {
        long long a=stoll(line2);
        long long b= stoll(line3);
        calc.compute(t,(int)a,(int)b);
    }
    
    return 0;
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
}