#include <iostream>
#include <cstdio>
using namespace std;
char a;
bool Error=1;
int b,c;
int main()
{
    cin>>b>>c;
    scanf("%c",&a);
    if(a=='/')
    {
        if(c==0)
        {
            cout<<"Divided by zero!";
            return 0;
        }
        cout<<b/c;
    }
    switch(a)
    {
        case '+':cout<<b+c;Error=0;break;
        case '-':cout<<b-c;Error=0;break;
        case '*':cout<<b*c;Error=0;break;
        case '/':Error=0;break;
    }
    if(Error)
    {
        cout<<"Invalid operator!";
    }
    return 0;
}

IDE错了 洛谷评测也错了