Problem:
Score : 300 points

Problem Statement

Given is a sequence of integers A_1, A_2, ..., A_N.
If its elements are pairwise distinct, print YES; otherwise, print NO.

Constraints

2 ≤ N ≤ 200000

1 ≤ A_i ≤ 10^9

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
A_1 ... A_N

Output

If the elements of the sequence are pairwise distinct, print YES; otherwise, print NO.

Sample Input 1

5
2 6 1 4 5

Sample Output 1

YES

The elements are pairwise distinct.

Sample Input 2

6
4 1 3 1 6 2

Sample Output 2

NO

The second and fourth elements are identical.

Sample Input 3

2
10000000 10000000

Sample Output 3

NO

Solution in C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>
int main(void)
{
          int n , j;
          int score = 0 ;
          scanf("%d", &n) ;
          int a[n] ;
          int i ;
          for ( i = 0 ; i < n ; i++)
          {
                    scanf("%d", &a[i]) ;
          }

          for ( i = 0 ; i < n ; i++)
          {
                    for( j = 1; j< n ; j++)
                    if(a[i]= a[j]) {
                              score++ ;
                    }
          }
          if(score == (n-1) ) printf("YES") ;
          else printf("NO") ;

}