#include <bits/stdc++.h>
using namespace std;
int main()
{
    unsigned long long a,b,c=2;
    for(cin>>a;a;--a)
    {
        cin>>b;
        for(int i=b-1;i>1;i-=2)
        {
            c=c*i;
        }
        cout <<c;
    }
}