#include <iostream>
#include <algorithm>
using namespace std;
int main(int argc, char **argv){
int num;
scanf("%d",&num);
int * A = new int[num];
for(int i=0; i<num; i++){
scanf("%d",&A[i]);
}
sort(A, A + num);
printf("%d", A[0] * A[num-1]);
return 0;
}