#include<stdio.h>
#define nmax 100
long long a[nmax];
int b[nmax];

int main()
{
 freopen("factoriale.in","r",stdin);
 freopen("factoriale.out","w",stdout); //factorialE :( eu scriam factorial
 
 int n,k;
    
 long long solutie=1;    
    
 int i,j,aux; 
 int maxim1=0,maxim2=0;
   
 scanf("%d%d",&n,&k);
 
 for(i=1; i<=n; ++i){
 scanf("%d",&aux);
 a[aux]=1;
 
 if( aux >maxim1)
 maxim1=aux;
 
 }
        for(i=100,j=0; i>1; --i){
        if( a[i] )
        ++j;
        
        a[i]=j;
        }
        
 for(i=2; i<=nmax && a[i]; ++i){
 
 if( !b[i])
   for(j=i+i; j<=maxim1 && j<=nmax; j+=i){
   b[j]=1;
   a[j]*=j;
   a[i]+=(a[j]/i);
   }
}  
        
        for(i=2; i<=100 && i<=maxim1; ++i){    
           if( a[i] && !b[i]){
            aux=a[i]%2;
            if(aux)
            solutie*=i;
            }
            
           }
               
        printf("%lld\n",solutie);

    
    return 0;
}