package main

import . "fmt"

func main() {
	var n int
	Scan(&n)
	a := make([]int, n)
	for i := range a {
		Scan(&a[i])
	}
	const T = (1 << 12)-1
	
	ans := 0
	col := make([]byte, n)
	for i := range col {
		col[i] = 'B'
	}
	
	tmp := make([]byte, n)

	for w := 0; w <= T; w++ {
		b := w ^ T
		ok := true
		bb, ww := 0, 0
		for i, e := range a {
			if (e&w)==(e&T) {
				tmp[i] = 'W'
				ww |= e
				continue
			}
			if (e&b)==(e&T) {
				tmp[i] = 'B'
				bb |= e
				continue
			}
			ok = false
		}
		if ok && (ww&bb) == 0 {
			if ww*bb > ans {
				ans = ww*bb
				copy(col, tmp)
			}
		}
	}
	Println(ans)
	Println(string(col))
}