s = gets.split(" ")

W = s[0].to_i
H = s[1].to_i
C = s[2]

if C=='B' 
    D='W'
else 
    D='B'
end
    
(1..H).each{ |i|
    (1..W).each{ |j|
        if i%2==1
            if j%2==1
                print C
            else
                print D
            end    
        else
            if j%2==1
                print D
            else
                print C
            end    
        end    
    }
    print "\n"
}