#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define all(x) (x).begin(), (x).end()
using ll = long long;
const ll MOD = 998244353;
#include<atcoder/all>
using namespace atcoder;
using mint = modint998244353;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  ll n;cin>>n;
  vector<ll> A(n);
  rep(i,n) cin>>A[i];
  vector<bitset<12>> B(n);
  rep(i,n){
    B[i] = bitset<12>(A[i]);
  }
  dsu uf(n);
  rep(i,12){
    vector<ll> v;
    rep(j,n){
      if(B[j][i]) v.push_back(j);
    }
    if(v.size()>1){
      rep(j,(int)v.size()-1){
        uf.merge(v[j],v[j+1]);
      }
    }
  }
  vector<pair<ll,ll>> G;
  map<ll,vector<int>> mp;
  for(auto g:uf.groups()){
    ll x=0;
    mp[uf.leader(g[0])]=g;
    for(auto i:g) x|=A[i];
    G.push_back({x, uf.leader(g[0])});
  }
  G.push_back({0, -1});
  sort(all(G));
  vector<ll> G1;
  for(auto p:G) G1.push_back(p.first);
  ll m = G.size();
  rep(i,m-1){
    G1[i+1]+=G1[i];
  }
  ll sum=G1.back();
  auto it=lower_bound(all(G1), G1.back()/2);
  vector<char> Ans(n,'W');
  ll q;
  if(*it*(sum-*it)>*(it-1)*(sum-*(it-1))){
    q=it-G1.begin()+1;
  }else{
    q=it-G1.begin();
  }
  rep(i,q){
    for(auto j:mp[G[i].second]){
      Ans[j]='B';
    }
  }
  cout<<max(*it*(sum-*it),*(it-1)*(sum-*(it-1)))<<endl;
  cout<<string(all(Ans))<<endl;
}