#include<iostream>
#include<vector>
#include<fstream>
#include<algorithm>
#include<numeric>


using namespace std;



int solve(vector<int> &seq, int cur, int rest)
{
  if(cur >= seq.size() || rest < seq[cur]) return -1;
  if(rest == seq[cur]) return cur + 1;
  // left
  int used = solve(seq, cur+1, rest - seq[cur]);
  if(used == -1) return -1;
  // right
  return solve(seq, used, rest-seq[cur]);
}

int main(void)
{
  ifstream cin("balance.in");

  int N;
  while(cin >> N && N){
    vector<int> seq;
    for(int i = 0; i < N; ++i){
      int a;
      cin >> a;
      seq.push_back(a);
    }
    bool success = false;
    int sum = 0;
    for(int i = 0; i < N; ++i){
      sum += seq[i];
      if(solve(seq, 0, sum) == N){
	success = true;
	break;
      }
    }
    cout << (success ? "yes" : "no") << endl;
  }
  return 0;
}