#include <iostream>
#include <cstdio>
using namespace std;

int main()
{
    int n;
    while(scanf("%d",&n) == 1)
    {
        int a[10000];
        for(int i = 0;i < n;i++)
        {
            scanf("%d",&a[i]);
        }
        int ok = 0;
        for(int i = 0;i < n;i++)
        {
            for(int j = 0;j < n;j++)
            {
                if(i == j) continue;
                for(int k = 0;k < n;k++)
                {
                    if(i == k || j == k) continue;
                    if(a[i] - a[j] == a[k])
                    {
                        ok = 1;
                    }
                }
            }
        }
        if(ok) printf("YES\n");
        else printf("NO\n");
    }

    return 0;
}