W,H,C=input().split()
W=int(W)
H=int(H)

ans=[]

if C=='B':
    for i in range(H):
        tmp = ''
        if i%2==1:
            for j in range(W):
                if j%2==1:
                    tmp+='B'
                else:
                    tmp+='W'
        else:
            for j in range(W):
                if j%2==1:
                    tmp+='W'
                else:
                    tmp+='B'
        ans.append(tmp)
else:
    for i in range(H):
        tmp = ''
        if i%2==1:
            for j in range(W):
                if j%2==1:
                    tmp+='W'
                else:
                    tmp+='B'
        else:
            for j in range(W):
                if j%2==1:
                    tmp+='B'
                else:
                    tmp+='W'
        ans.append(tmp)

print('\n'.join(ans))