#include <iostream>
#include<cmath>
using namespace std;
int main()
{
int *v,*prime,n,i,j,ok;
v= new int [20];prime=new int [20];
//n<20
cin>>n;
for(i=1;i<=n;i++)
{cin>>v[i];prime[i]=0;}
for(i=2;i<=n;i++)
{
ok=1;
for(j=2;j<=sqrt(i);j++)
if(i%j==0)
ok=0;
if(ok)
prime[i]=1;//i este numar prim
}
for(i=1;i<=n;i++)
if(prime[i]==0)cout<<v[i];
return 0;
}