#include<map>
#include<vector>
#include<cstring>
#include<algorithm>
#include<cstdio>
#include<iostream>
using namespace std;
int vis[1005];
int a[105];
int main(){
    int m,n,i,j,k,t;
    while(scanf("%d",&m)==1){
        memset(vis,0,sizeof(vis));
        for(i=1;i<=m;i++) scanf("%d",&a[i]);
        for(i=1;i<=m;i++) vis[a[i]]++;
        for(i=1;i<=m;i++){
            for(j=i+1;j<=m;j++){
                if(vis[abs(a[i]-a[j])]){
                    int num=abs(a[i]-a[j]);
                    if(a[i]==num&&a[j]==num){
                        if(vis[num]>=3){
                            cout<<"YES"<<endl;
                            goto l;
                        }
                        else goto z;
                    }
                    if(a[i]==num||a[j]==num){
                        if(vis[num]>=2){
                            cout<<"YES"<<endl;
                            goto l;
                        }
                        else goto z;
                    }
                    cout<<"YES"<<endl;
                    goto l;
                }
                z:;
            }
        }
        cout<<"NO"<<endl;
        l:;
    }
}