#include <algorithm>

#include <iostream>

#include <cstdio>

using namespace std;

long long a [];

int main()

{

    int n;

    cin >> n;

    int num = ;

    while(n--)

    {

        if(num > )

        {

            break;

        }

        long long temp;

        cin >> temp;

        int flag = ;

        for(int i = ;i < num;i++)

        {

            if(a[i] == temp)    flag = ;

        }

        if(flag) a[num++] = temp;

    }

    if(num ==  || num == )    printf("YES\n");

    else if(num == )

    {

        sort(a,a+);

        if(a[]+a[] == *a[]) printf("YES\n");

        else    printf("NO\n");

    }

    else

    {

        printf("NO\n");

    }

    return ;

}