#include <iostream>#include <climits>using namespace std;
int main(){int n,max,i,j,x,OK;cin>>n;max=INT_MIN;for(i=1;i<=n;i++) {cin>>x;OK=0; for(j=2;j<=x/2;j++) if(x%j==0)OK=1; if(OK==0)if(x>max)max=x; }cout<<max; return 0;}
//cam asta ar fi cu placere :D