#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
int main(){
  int N;
  cin >> N;
  int M = 1000000;
  vector<int>C(M+1,0);
  for(int i=0;i<N;i++){
    int a;cin >> a;
    C[a]^=1;
  }
  vector<int>p(M+1,1);
  vector<int>gs(M+1,0);
  for(int i=2;i<=M;i++){
    if(p[i]==0)continue;
    for(int j=2*i;j<=M;j+=i){
      p[j] = 0;
    }
    for(int j=i;j<=M;j+=i){
      if(C[j]==0)continue;
      int y = j;
      while(y%i==0)y/=i,gs[j]++;
    }
  }
  int g = 0;
  for(int i=1;i<=M;i++)g^=gs[i];
  cout << (g?"white":"black") << endl;
  return 0;
}