Yaroslav and Permutations

Description:

Input:

The first line contains integer n (1 ≤ n ≤ 100) — the number of elements in the array. The second line contains n integers a₁, a₂, ..., a_n (1 ≤ a_i ≤ 1000) — the array elements.

Output:

In the single line print "YES" (without the quotes) if Yaroslav can obtain the array he needs, and "NO" (without the quotes) otherwise.

Sample Input:

1
1

Sample Output:

YES

Sample Input:

3
1 1 2

Sample Output:

YES

Sample Input:

4
7 7 7 7

Sample Output:

NO

Note:

In the first sample the initial array fits well.

In the second sample Yaroslav can get array: 1, 2, 1. He can swap the last and the second last elements to obtain it.

In the third sample Yarosav can't get the array he needs.