#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
using namespace std;
#define Lowbit(x) ((x)&(-(x)))
#define ll long long
#define mp make_pair
#define ff first
#define ss second
const int MAXN=1005;

int a[MAXN];

int cmp(const void *a, const void *b){
    return *(int *)a - *(int *)b;
}

int main(){
    #ifdef LOCAL
        freopen("1.in", "r",stdin);
        //freopen("1.out", "w", stdout);
    #endif
    int i;
    int N;
    while(~scanf("%d", &N)){
        int sum = 0;
        double mid;
        for(i=1; i<=N; ++i){
            scanf("%d", &a[i]);
            sum += a[i];
        }
        qsort(a+1, N, sizeof(a[0]), cmp);
        mid = (1.0*sum)/N;
        if(fabs(a[(N+1)/2]-mid)<1e-9||mid>a[(N+1)/2]){
            printf("NO\n");
        }
        else{
            printf("YES\n");
        }
    }
    return 0;
}