#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <limits.h>
#include <stdbool.h>

long int largestValue(int A_size, int* A) {
    // Return the largest value of any of A's nonempty subarrays.
    int b[100],i,j,k,s=0,si,fs,ss,pos1,pos2,size,t,t1,t2,t3;
    k=si=0;
    j=2;
    fs=A[0];
    pos1=0;
    ss=A[1];
    pos2=1;
    if(fs>ss)
    {
     t=fs;
     fs=ss;
     ss=t;  
    t3=pos1;
     pos1=pos2;
     pos2=t3;  
    }
    for(i=2;i<A_size;i++)
    {
        if(A[i]<fs)
        {
            ss=fs;
            pos2=pos1;
            fs=A[i];
            pos1=i;
        }
        else if(A[i]<ss)
        {ss=A[i];
        pos2=i;}
        
    }
    t1=A[pos1];
    A[pos1]=A[0];
    A[0]=t1;
    t2=A[pos2];
    A[pos2]=A[1];
    A[1]=t2;
    printf("%d",A[0]);
    
    while(j<A_size)
    {
        for(i=j+1;i<A_size;i++)
        {
            b[k]=A[j]*A[i];
            k++;
            si++;
        }
        j++;
    }
    //for(i=0;i<si;i++)
        //printf(b[i]);
    for(i=0;i<si;i++)
    {
        s+=b[i];
    }
    return(s);
}

int main() {
    int n; 
    scanf("%i", &n);
    int *A = malloc(sizeof(int) * n);
    for (int A_i = 0; A_i < n; A_i++) {
       scanf("%i",&A[A_i]);
    }
    long int result = largestValue(n, A);
    printf("%ld\n", result);
    return 0;
}