using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var n = NN;
        var a = NList;
        var w = 0;
        var b = 0;
        var ans = new char[n];
        var isw = true;
        for (var i = 12; i >= 0; --i)
        {
            var count = 0;
            for (var j = 0; j < n; ++j)
            {
                if (ans[j] == 0 && ((a[j] >> i) & 1) != 0) ++count;
            }
            if (count > 0)
            {
                var nlist = new List<int>();
                for (var j = 0; j < n; ++j)
                {
                    if (ans[j] == 0)
                    {
                        if (((a[j] >> i) & 1) != 0)
                        {
                            if (isw)
                            {
                                w |= a[j];
                                ans[j] = 'W';
                            }
                            else
                            {
                                b |= a[j];
                                ans[j] = 'B';
                            }
                        }
                    }
                }
                isw = false;
            }
        }
        WriteLine(w * b);
        WriteLine(string.Concat(ans));
    }
}