#include<stdio.h>
#define maxn 100000
int main()
{
int a[maxn];
int n;
while(scanf("%d",&n)!=EOF&&n)
{
int ans=1;
for(int i=0;i<n;i++)
{
scanf("%d",&a[i]);
if(a[i]%2==1)
ans*=a[i];
}
printf("%d\n",ans);
}
return 0;
}