#include<cstdio>
#include<cstring>
#include<algorithm>

using namespace std;

int a[1010], t;

bool cmp(int x, int y)
{
    return x > y;
}

int main()
{
    int n;
    while(~scanf("%d", &n))
    {
        for(int i = 1; i <= n; i++) scanf("%d", &a[i]);
        sort(a + 1, a + n + 1, cmp);
        for(int i = 1; i <= n; i++)
        {
            t = n;
            for(int j = i + 1; j <= n; j++)
            {
                while(t > j && a[i] - a[j] > a[t]) t--;
                if(t > j && a[i] - a[j] == a[t])
                {
                    puts("YES");
                    goto bomb;
                }
                if(t <= j) break;
            }
        }
        puts("NO");
        bomb:;
    }
    return 0;
}