import java.util.Scanner;
 
class CalDifference{
 
        public static void main(String[] k){
        
        int n, sumOfSq, sqOfSums, diff;
        int[] num; 
        int[] numSq;    
 
        Scanner sc = new Scanner(System.in);
        
        System.out.println("Enter the num of Elements to be entered");
        n = sc.nextInt();
        
        num = new int[n];
        numSq = new int[n];
 
        inputElements(num,n);
        sqOfElements(num,numSq,n);
        sumOfSq  = sum(numSq,n) * sum(numSq,n);
        sqOfSums = sum(num,n) * sum(num,n);     
        diff     = sumOfSq - sqOfSums;
 
        }
 
        public static void inputElements(int[] a, int n){
 
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter Elements");
 
                for(int i=0 ; i<n ; i++)
                {
                a[i] = sc.nextInt();
                }
        }
        
        public static void sqOfElements(int[] a,int[] aSq, int n){
        
                for(int i=0 ; i<n ; i++)
                {
                aSq[i] = a[i] * a[i];
                }
        }
 
        public static int sum(int[] a, int n){
                
        int sum = 0;
 
                for(int i=0 ; i<n ; i++)
                {
                sum = sum + a[i];
                }
        return sum;
        }
}