#include<iostream>
using namespace std;
int main()
{
    int a,b;
    cin>>a;
    cin>>b;
    try
    {
        if(a<=0||b<=0)
        {
            throw"Invalid input";
        }
        int c;
        c=ab;
        cout<<c;
    }
    catch(const char*a)
    {
        cout<<a;
    }
    return 0;
}