#include<iostream>
using namespace std;
class Calculator {
    public:
    int calculate(int t, int a, int b){
        if(t <= 0 || t > 4){
            cout << "Invalid input" << endl;
            return 0;
        }
        switch(t){
            case 1: return a + b;
            case 2: return a - b;
            case 3: return a * b;
            case 4: return a / b;
        }
        return 0;
    }
    double calculate (int t, double a, double b){
        if (t <= 0 || t > 4) {
            cout << "Invalid input" << endl;
            return 0.0;
        }
        switch(t) {
            case 1: return a + b;
            case 2: return a - b;
            case 3: return a * b;
            case 4: return a / b;
        }
        return 0.0;
    }
};
int main(){
    int t;
    cin >> t;
    double a, b;
    cin >> a >> b;
    if(a<0|b<0||t<0){
        cout <<"Invalid input";return 0;
    }
    if(a==0||b==0||t==0)
    {
        cout<<"Division by zero";return 0;
    }
    else 
    Calculator calc;
    if(int(a) == a && int(b) == b){
        int res = calloc.Calculate(t, int(a), int(b));
        if (!(t == 4 && (a == 0 || b == 0)) && t > 0 && t <= 4)
        cout << res << endl;
    }
    else {
        double res = calloc.Calculate(t, a, b);
        if(!(t == 4 && (a == 0.0 || b == 0.0)) && t > 0 && t <= 4)
        cout << res << endl;
    }
    return 0;
}