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: Runtime Error)

#include <stdio.h>
#include <stdlib.h>

int main(void){
    char *result = "Yes";
    int n = 0;
    int i, j;
    int *value;
    value = ( int* ) malloc( sizeof (int) * n );

    scanf( "%d", &n );

    for( i = 0; i < n ; i++ ){
        scanf( "%d", &value[i] );
    }

    for( i = 0; i < n ; i++ ){
        for( j = 0; j < n ; j++ ){
            if( value[i] == value[j] && i != j ){
                result = "No";
            }
        }
    }

    printf( "result = %s\n", result );

    free( value );
    return 0;
}