#include
#include
using namespace std;
int x,n;
double r;
int main()
{
r = 0;
cin >> n;
double *ptrarray = new double[n];
for (int i = 0; i < n; i++)
{
cin >> x;
ptrarray[i] = cos(2*x) + 3;
if (fmod(ptrarray[i],2) != 0
{
r=r*ptrarray[i];
}
}
cout << r;</strong>
return 0;
}