import sys
input = lambda : sys.stdin.readline().rstrip()

sys.setrecursionlimit(2*10**5+10)
write = lambda x: sys.stdout.write(x+"\n")
debug = lambda x: sys.stderr.write(x+"\n")

U = 0
D = 1
L = 2
R = 3
d = {
    U: "U",
    D:"D",
    L:"L",
    R:"R"
}
H,W,x = list(map(int, input().split()))
h = (H+1)//2
w = (W+1)//2
M = h*w if h*w%4==0 else h*w-1
if not (H+W-2<=x<=2*(M-1) and x%2==0):
    print(-1)
else:
    ans = [[0]*W for _ in range(H)]
    for i in range(1,H,2):
        for j in range(1,W,2):
            ans[i][j] = 1
    for i in range(H):
        for j in range(1,W,2):
            ans[i][j] = 1
    vals = []
    def sub0(h,w,v):
        if w==2:
            if v%2==1:
                return None
            nokori = h-1
            while v>0:
                v -= 2
                vals.extend([R, D, L, D])
                nokori -= 1
            for _ in range(nokori):
                vals.append(D)
            vals.append(R)
            return 0
        else:
            vals.extend([D]*(h-1)+[R])
            ans[-1][W-2*w] = 0
            return sub1(h,w-1,v)
    def sub1(h,w,v):
        if v==0:
            vals.extend([R]*(w-1))
            for j in range(W-2*w, W):
                ans[-1][j] = 0
            return 0
        elif v<=2*(h-1):
            assert w>=2 and v%2==0
            vv = v//2
            vals.extend([U]*vv)
            vals.append(R)
            vals.extend([D]*vv)
            vals.extend([R]*(w-2))
            ans[H-1-vv*2][W-2*w] = 0
            for j in range(W-2*w+2,W):
                ans[-1][j] = 0
            return 0
        else:
            vals.extend([U]*(h-1))
            vals.append([R])
            ans[0][W-2*w] = 0
            return sub0(h,w-1,v-(h-1))
    v = x//2-(h-1+w-1)
    sub0(h,w,v)
    for l in ans:
        write("".join(["#" if l[i] else "." for i in range(len(l))]))