#include <bits/stdc++.h>
#include <stdlib.h>
using namespace std;
#define rep(i, a, n) for(ll i = a; i < n; i++)
#define rrep(i, a, n) for(ll i = a; i >= n; i--)
#define inr(l, x, r) (l <= x && x < r)
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define all(x) (x).begin(), (x).end()
//constexpr ll MOD = 1000000007;
constexpr ll MOD = 998244353;
constexpr int IINF = 1001001001;
constexpr ll INF = 1LL<<60;
template<class t,class u> void chmax(t&a,u b){if(a<b)a=b;}
template<class t,class u> void chmin(t&a,u b){if(b<a)a=b;}

ll gcd(ll a, ll b){
    if(a%b == 0){
      return b;
    }else{
      return gcd(b, a%b);
    }
}

ll lcm(ll a, ll b){
    return a*b / gcd(a, b);
}

ll powMod(ll x, ll n, ll mod) {
    if (n == 0) return 1 % mod;
    ll val = powMod(x, n / 2, mod);
    val *= val;
    val %= mod;
    if (n % 2 == 1) val *= x;
    return val % mod;
}

int main() {
    ll n; cin >> n;
    vector<ll> a(n);
    vector<pll> b(n);
    rep(i,0,n) cin >> a[i], b[i] = {a[i],i};
    ll num = 0;
    vector<ll> ans(n,0);
    sort(all(b), greater<pll>());
    {
        vector<ll> na(n,0);
        ll n0 = b[0].first, n1 = 0;
        na[b[0].second] = 0;
        rep(i,1,n){
            auto [x, id] = b[i];
            if(n0&x){
                n0 |= x;
                na[id] = 0;
            }
            else{
                n1 |= x;
                na[id] = 1;
            }
        }
        if((n0&n1) == 0) swap(ans,na);
        num = n0*n1;
    }
    

    cout << num << endl;
    for(auto x: ans) cout << (x == 0 ? 'W' : 'B');
    cout << endl;
    return 0;
}