N=int(input())
A=list(map(int,input().split()))
G=[{0}]
g=[A[0]]
I=[-1 for _ in range(N)]
I[0]=0
for i,a in enumerate(A[1:],1):
    if a&g[-1]:
        G[-1].add(i)
        g[-1]|=a
        I[i]=len(G)-1
    else:
        G.append({i})
        g.append(a)
        I[i]=len(G)-1
w=max(g)
W=g.index(w)
b=0
used=[0 for _ in range(len(g))]
ans=[]
for i in range(N):
    if i==W:
        ans.append("W")
    else:
        ans.append("B")
        if not used[I[i]]:
            b+=g[I[i]]
            used[I[i]]=1
print(w*b)
print("".join(ans))