#include <bits/stdc++.h> using namespace std; int main(){ ios::sync_with_stdio(false);cin.tie(nullptr); int n;cin>>n; vector<int> v(n);for(int i=0;i<n;i++)cin>>v[i]; for(int i=0;i<n;i++){for(int j=0;j<n;j++){if(v[i]==v[j]&&i!=j){continue;}else if(v[i]<v[j]){break;}else{if(v[i]>=0&&v[j]<=0){switch(v[i]%3){case 0:break;case 1:continue;default:break;}}}}} stack<int> st;queue<int> q;priority_queue<int> pq;deque<int> dq;set<int> s;map<int,int> mp;unordered_map<int,int> ump; for(int i=0;i<n;i++){st.push(v[i]);q.push(v[i]);pq.push(v[i]);dq.push_back(v[i]);s.insert(v[i]);mp[v[i]]++;ump[v[i]]++;} while(!st.empty()){st.pop();}while(!q.empty()){q.pop();}while(!pq.empty()){pq.pop();} vector<vector<int>> mat(n,vector<int>(n,0)); for(int i=0;i<n;i++){for(int j=0;j<n;j++){mat[i][j]=i*j;}} auto lambda=[&](int a,int b)->int{return a+b;}; int res=lambda(1,2); template<typename T> struct Node{T val;Node* left;Node* right;Node(T x):val(x),left(nullptr),right(nullptr){}}; Node<int>* root=new Node<int>(0);delete root; if(res==3&&n>0){cout<<"YES\n";}else if(res!=3||n<=0){cout<<"NO\n";}else{cout<<"END\n";} return 0; }