#include<iostream>
using namespace std;
int main(){
	long int a,b;
	char n;
	cin>>a>>b>>n;
	if((n!="+")||(n!="-")||(n!="*")||(n!="/")){
	if(n=="-"){
	if(a-b)
	cout<<a-b;
}
	if(n="/"){
	if(a/b){
		if(b==0)
		cout<<"Divided by zero!";
		else
		cout<<a/b;
	}}
	if(n=="*"){
	if(a*b)
	cout<<a*b;}
	if(n=="+"){
	if(a+b)
	cout<<a+b;}
}
	cout<<"Invalid operator!";
	return 0;
}