#include <iostream>
#include <cstdio>
#include <cstring>

using namespace std;

int a[105];
int cnt[1005];

int main(){
    int n;
    while(scanf("%d",&n) != EOF){
        memset(cnt,0,sizeof(cnt));
        for(int i = 0;i < n;i++){
            scanf("%d",&a[i]);
            cnt[a[i]] ++;
        }
        int tmp;
        int flag = 0;
        for(int i = 0;i < n;i++){
            for(int j = 0;j < n;j++){
                if(i != j){
                    tmp = a[i]-a[j];
                    if(tmp < 0)
                        continue;
                    cnt[a[i]]--;
                    cnt[a[j]]--;
                    if(cnt[tmp]){
                        printf("YES\n");
                        flag = 1;
                        break;
                    }
                    cnt[a[i]]++;
                    cnt[a[j]]++;
                }
            }
            if(flag == 1)
                break;
        }
        if(flag == 0){
            printf("NO\n");
        }


    }
    return 0;
}