A. Yaroslav and Permutations

time limit per test

2 seconds

memory limit per test

256 megabytes

input

standard input

output

standard output

Yaroslav has an array that consists of n integers. In one second Yaroslav can swap two neighboring array elements. Now Yaroslav is wondering if he can obtain an array where any two neighboring elements would be distinct in a finite time.

Help Yaroslav.

Input

The first line contains integer n (1 ≤ n ≤ 100) — the number of elements in the array. The second line contains n integersa₁, 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 test(s)

input

1
1

output

YES

input

3
1 1 2

output

YES

input

4
7 7 7 7

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.

解题说明：此题的意思是通过交换一列数中相邻位置的数保证两个相同的数不连续出现，由于相邻交换能把一个数换到任何位置，其实只要保证这组数中相同的数不要占据一半以上即可。用数组来统计每个数字出现的次数，对出现次数最多的数加以判断即可。

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cstring>
#include <string>
#include <algorithm>
using namespace std;

int main() 
{
	int n,a[1001],i,temp;
	int max;
	scanf("%d",&n);
	memset(a,0,sizeof(a));
	max=0;
	for(i=0;i<n;i++)
	{
		scanf("%d",&temp);
		a[temp]++;
		if(a[temp]>max)
		{
			max=a[temp];
		}
	}
	if(max>(n+1)/2)
	{
		printf("NO\n");
	}
	else
	{
		printf("YES\n");
	}
	return 0;
}