#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define srep(i,l,r) for(ll i=l;i<=r;i++)
#define irep(i,r,l) for(ll i=r;i>=l;i--)
using ll = long long;
using ld = long double;
const ll mod=998244353;
#define vout(v) for(auto i :v) cout<<i<<" ";
#define INF 9223300000000000000ll
#define Winf 5e12
#define nl "\n"
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define vl vector<ll>
#define pb push_back
#define vc vector<char>
#define vb vector<bool>
#define uniq(x) sort((x).begin(),(x).end());(x).erase(unique((x).begin(),(x).end()),(x).end())
#define eb emplace_back



void no(void) { cout<<"No"<<nl;}
void yes(void) {cout<<"Yes"<<nl;}
void yn(bool a) {
    cout<<(a ? "Yes":"No")<<nl;
}


vector<ll> dx={-1,0,1,0,1,1,-1,-1};
vector<ll> dy={0,-1,0,1,-1,1,-1,1};

bool isin(ll i,ll j,ll h,ll w) {
    if(i<0 || i>=h || j<0 || j>=w) return false;
    return true;
}

template<typename T> bool chmin(T& a, T b){if(a > b){a = b; return true;} return false;}
template<typename T> bool chmax(T& a, T b){if(a < b){a = b; return true;} return false;}


template<class T>T vecmax(const vector<T>&v){return *max_element(all(v));}
template<class T>T vecmin(const vector<T>&v){return *min_element(all(v));}

ll safemod(ll num,ll rule) {
    return (num%rule+rule)%rule;
}

struct res {
    vl ws;
    vl bs;
    ll w;
    ll b;
};
//ファイル読み込みは第二フォルダから ex:include "mathtype/hoge.hpp"
int main() {
    ll n; cin>>n;
    vl a(n);
    rep(i,n) cin>>a[i];
    function<res(ll,ll,ll,vl,vl)> rec=[&](ll size,ll w,ll b,vl ws,vl bs)->res {
        if(size==n) return {ws,bs,w,b};
        ll best=-1;
        res bestset={{},{},-1,-1};
        if((a[size]&b)==0) {
            ll nw=w|a[size];
            vl nws=ws;
            nws.pb(size);
            auto [rws,rbs,rw,rb]=rec(size+1,nw,b,nws,bs);
            ll prod=rw*rb;
            if(prod>best) {
                best=prod;
                bestset={rws,rbs,rw,rb};
            }
        }
        if((a[size]&w)==0) {
            ll nb=b|a[size];
            vl nbs=bs;
            nbs.pb(size);
            auto [rws,rbs,rw,rb]=rec(size+1,w,nb,ws,nbs);
            ll prod=rw*rb;
            if(prod>best) {
                best=prod;
                bestset={rws,rbs,rw,rb};
            }
        }
        return bestset;
    };
    auto [ws,bs,aw,ab]=rec(0,0,0,vector<ll>(0),vector<ll>(0));
    cout<<aw*ab<<nl;
    string s;
    set<ll> setW(all(ws));
    rep(i,n) {
        if(setW.count(i)) s+="W";
        else s+="B";
    }
    cout<<s<<nl;
}