#include <iostream>
using namespace std;
int main()
{
int a[]={2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37}, n;
while(1){
if ((cin >> n) >= 0 && n < sizeof(a)/sizeof(a[0]))
cout << "a[" << n << "] = " << a[n] << endl;
else break;
}
return 0;
}