# hello worldと表示する

a=input().split()
for i in range(int(a[1])):
    for j in range(int(a[0])):
        if (i%2==0) and (j%2==0):
            print(a[2],end="")
        elif (i%2==1) and (j%2==1):
            print(a[2],end="")
        
        else:
            if a[2]=="W":
                print("B",end="")
            else:
                print("W",end="")
    print()