w,h,c = input().split()
w,h = int(w), int(h)

for i in range(h):
    if i%2==0:
        if c=='W':
            line = 'WB'*(w//2)
        else:
            line = 'BW'*(w//2)
        
        if w%2!=0 and w!=1:
            line += line[-2]
        elif w==1:
            line = c
    
    else:
        if c=='W':
            line = 'BW'*(w//2)
        else:
            line = 'WB'*(w//2)
        
        if w%2!=0 and w!=1:
            line += line[-2]
        elif w==1:
            if c=='W':
                line = 'B'
            else:
                line = 'W'
    
    print(line)