#451 calcul

#include <iostream>

using namespace std;

int main()
{
    int n;
    cin>>n;
    if(n<=15)
    cout<<n*n;
    else
    if(n>=16 && n<=30)
    cout<<(n%10)+n/10;
    else
    cout<<(n%10)*(n/10);
    return 0;
}