#include <bits/stdc++.h>
using namespace std;
#define ALL(x) (x).begin(), (x).end()
#define REP(i, n) for(ll i=0; i<(ll)(n); i++)

template<typename T> bool chmax(T& a, T b) { return a<b ? a=b, true : false; }
template<typename T> bool chmin(T& a, T b) { return a>b ? a=b, true : false; }
using ll=long long; const int INF=1e9+10; const ll INFL=4e18;
using VI=vector<int>; using VVI=vector<VI>; using VL=vector<ll>; using VVL=vector<VL>;
using PL=pair<ll,ll>; using VP=vector<PL>; using WG=vector<vector<pair<int,ll>>>;

#ifdef LOCAL
#include "./debug.hpp"
#else
#define debug(...)
#define print_line
#endif


//----------------------------------------------------------

void solve() {
    ll N; cin>>N;
    VL A(N); REP(i,N) cin>>A[i];

    ll ans=-1;
    ll L=12;
    string str;
    REP(bt,1<<L) {
        ll black=0, white=0;
        REP(i,L) {
            if(bt>>i&1) black+=1<<i;
            else white+=1<<i;
        }

        ll b=0, w=0;
        bool ok=true;
        string res;
        REP(i,N) {
            if((black|A[i])==black) b|=A[i], res+='B';
            else if((white|A[i])==white) w|=A[i], res+='W';
            else ok=false;
        }

        if(ok) if(chmax(ans,b*w)) str=res;
    }

    cout<<ans<<endl;
    cout<<str<<endl;
}

int main() {
    ios::sync_with_stdio(false); cin.tie(nullptr);
    //cout<<fixed<<setprecision(15);
    int T=1;
    //cin>>T;
    while(T--) solve();
}